But I'm a little concerned about your mindset. Specifically, your concern that a provider would refuse you for being too small makes me worried that you are going into this thinking that providers seek a certain level of pleasure, and that they may perceive you as being unable to provide it and you will be summarily shown the door. Understand, and never forget, that this is not dating, this is business, and the good providers (as I personally know Tobi to be and as I suspect and will soon find out that Julia is) make your pleasure their business and take pride in seeing you leave the session happy and satisfied. I believe this is equal parts affinity for the trade (the best really do like their jobs) and that they are smart businesswomen who want their businesses to be successful. So please do get lost in the fantasy, but not too lost, and enjoy yourself. And you might also want to remember that the size thing in pornos is for us, not for them.
Quick summary about my situation. I'm in my late 20's and have been a workaholic most of my life. Because of that, I don't have much sexual experience (not a virgin, though). I recently landed a sweet job with a great paycheck and thought I need to start enjoying myself more. I can't think of a better way than to become a hobbyist 
I'm pretty sure I can't directly ask providers about this but there are 2 things that worry me. The first being my inexperience I mentioned above. Do some providers care about that? The other thing is something I'm even more concerned about. I'm not very well endowed. In fact, I'm very below average. Which leads me to this next newbie question - can a provider refuse to do anything if you're very small? I'm sure I can't ask them this beforehand so I'm a little worried about seeing someone, having them look at me, then just walking away from the whole thing, thus wasting everyone's time and probably my own money since a deposit is usually needed.
To add to all that, I have fantasies about being with pornstars. I have the money but I know they're used to wayyyyy bigger sizes than I am. Is it common for them to refuse to do anything after a deposit because of everything I mentioned? Any input is appreciated. Thanks.
But seriously - if you're a halfway decent guy and pick any kind of halfway decent provider the things you're worried about will be irrelevant. They'll make you feel great regardless of your perceived 'shortcomings'.
We don't give a fuck how inexperienced or small you are. I promise you every single one of us has been with someone less experienced and smaller than you. Just be well-groomed and non-douchey, and everything will be just fine.
aside from your needless worries about being "undersized" is the need for a deposit. A deposit is needed only if you are asking the lady to spend money on something just for you and where she will be out that money if you are a no show. Something like booking a special hotel for you, taking a three hour drive to see you, or having to buy a special toy or outfit just for you. Other than those narrow situations do NOT send a provider a deposit.
There are lot of threads here full of great advice on a whole host of subjects, do yourself a favor, stop worrying about your small equipment and educate yourself here about how to have the best time with the least amount of risk.
One last thing on the subject, the only thing you might have to worry about if you are extremely small is a few positions might not be practical if you are too short, other than that don't worry about it, you are there for your pleasure and her income. Be clean, be respectful, and you won't have a bit of problems in re to your size.
But I'm a little concerned about your mindset. Specifically, your concern that a provider would refuse you for being too small makes me worried that you are going into this thinking that providers seek a certain level of pleasure, and that they may perceive you as being unable to provide it and you will be summarily shown the door. Understand, and never forget, that this is not dating, this is business, and the good providers (as I personally know Tobi to be and as I suspect and will soon find out that Julia is) make your pleasure their business and take pride in seeing you leave the session happy and satisfied. I believe this is equal parts affinity for the trade (the best really do like their jobs) and that they are smart businesswomen who want their businesses to be successful. So please do get lost in the fantasy, but not too lost, and enjoy yourself. And you might also want to remember that the size thing in pornos is for us, not for them.
Like most have already said here most providers are more interested in the size of your bankroll then size of your member. Tobi's advice is correct just show up polite , clean and don't act like a douche and you'll be fine . Why I always do my best to make sure my partners are enjoying themselves remember the here to please you.
While there always some bad apples in this profession like every else in life . Most quality providers want you to have a good time . Some for business reasons (repeat clients = more money ) and some just take pride in what they do and try there best to make sure you leave happy, especial if you treat them with respect .
As for the porn star fantasy . I've been with over a dozen " porn stars " including being a semi regular with a fairly well known UTR star . What I've learned from hours of pillow talk and gossip about the industry is the keyword is fantasy. These woman are "actresses" selling a fantasy . They do things on camera they don't always like or enjoy in real life and often work with male talent they don't even like . As unbelievably as it sounds not every woman enjoys getting "speared" with some guy's 12 inch member for eight hours on set.
This advice you received goes double for porn stars who provide . Remember these girls walk around with a scarlett A so to speak .While normal providers can always escape into there private lives when they need a break .These girls are always in the public eye and you won't believe the shit they can get from random strangers . If you treat them with some respect and don't treat them like a piece of meat you will be surprised how well they will treat you despite your size .
if you are too BIG. Small is not a problem.
Very well endowed guys have way more issues with things than the OP ever will. Personally I can do more and for longer with a small guy and that is my preference.
Clients have varying amounts of experience... I would suggest you select providers in the MILF range... late 20s to early 30s... who have enough experience to be a good partner. I think the barely legal (18-20) expect a guy to be more push button & don't want to put the effort out to be a great lover. IMHO, They have the hot looks of youth, so they don't have to.
You need to check proflies for real pictures & completes services as promised. In any event you need to read complete reviews & select well reviewed providers 6 to 10 or more reviews & some reviews be experienced reviewers (equal numbers of reviews so they know whart they are talking about.) JUst because they claim "well reviewed" in an ad does not mean the reviews are good. I've followed links to TER reviews & was amazed that some were BAD! The gal must have thought noone would actually read them!
You may think you are "small" but there is a normal range & it is quite wide. Again experiemced ladies know the positions which work best for each size & type.
Be respectful & be clean... & you'll do fine.
An advance deposit should not be required for a typical encounter but cash is. Typically the donation is left on a table, dresser or bathroom counter. If her web site has instructions, you should follow them but otherwise, just leave on a convient place. Do not watch it nor hand it to her directly unless she requests it. Sometimes a gal will check the donation, other times not. You want to ALWAYS avoid discussion of sex acts & money as this is the definition of prostitution which is illegal in most of the US.
If her web site or ad does not specify a donation you can verify the amount but always "for her time". TER proces are usually right but occasionally not up to date. I'd carry a bit spare cash to be sure but keep it put away.
The standard program is donation in an unmarked unsealed envolupe... I stopped envolupes some time ago as they don't pocket carry well. I set the donation aside & secure with a paper clip to be sure it stays together.
Put the porn stars n the back burner for now. Know that providers (even porn stars) won't or shouldn't offer intercourse (FS) without a condom. Just because everyone in a movie is tested... doesn't mean they will do so to clients. Every so often there is a disease outbreak in the porn industry... just hold off on that scene until you have more experience.
When you are working with a girl for the first time is it normal for them to ask for your work phone number and place of work? Do you know why they ask for this info? Just want to keep this as confidential as possible.
Thank you all for the responses. I definitely feel a lot better about this whole thing now. harborview, I actually was planning on putting pornstars on hold for a while even though I don't really care if have to use a condom. I'm definitely all about playing things safe. The biggest reason I wasn't planning on going straight to a pornstar was because it looks like most of them request references. I'll probably see if I can find some newbie friendly providers in my area before I look into that. That whole situation is a different issue for a different thread, though
I'm completely new to TER so I didn't even realize providers look at these forums and even respond. So, a big thank you to Tobi and Julia. Hearing that type of reassurance straight from the source really put me at ease. Again, thanks to everyone else, too
Dude size only matters if you're Big. Don't even concern yourself about it.