For a while now I have debated about getting an erotic massage. It seems to be that almost all "legit" asian massage parlors do this sort of service, but im not sure if its assumed when you walk in the door or if you have to ask.  

Also, what is a table shower?

Any info/advice would be greatly appreciated.

It like getting some from a stripper you also have to know how to ask and tip.

but to answer the basic question, NO NO, NO, not all legit asian massage places offer extras (which is what I'm assuming you mean).  Now if you are talking about a place with a table shower, I think it's pretty close to a 100% chance they offer extras.  A table shower just involves you laying flat on a table, and the lady thoroughly washing you on both sides with a shower hose.  Nice little fun time.  I've also been to places where it's just a standing shower.

a handheld shower wand.  They'll first rinse you down (you're nekkid, she's clothed) while laying face down on the table, then use a body scrub, and rinse, then soap, and rinse, then you flip over and she does the front.  She'll have you sit up and will rinse off your upper body, then you leave the table and she dries you off before leading you back to the massage room.  You're squeaky clean, she's more comfortable touching you, and it's really a great way to be pampered.

Check the ads for a place, see if table shower is an option, and then just say yes when they ask if you want one.  They'll lead you to your massage room first where you disrobe, put on a set of sandals, wrap a towel around yourself, and then she'll return and lead you to the shower room.  I leave all my stuff in the room, and have never had anything stolen (knock on wood) but if you're uncomfortable then take a ziploc bag to put your valuables in and keep it with you.  They might have a small mesh bag to put stuff in, but can't count on it.

Being your first time I'd recommend a midmorning time as they tend to be fairly empty then and you won't feel conspicuous.  Later times will have more ladies on staff, some of whom are more daring.

Getting a happy ending depends on the girl, the place, the vibe, the timing, you, the tip etc.  If you're erect when they take you back for the shower, that's a good indication to her that you're interested in extras.  If you touch her body (nicely, and be sure to ask if it's okay) that's another point in your favor.  Might take several trips for you to be comfortable enough to try the above, or for them to accept you as a "safe" client.

Good luck!  And remember, if nothing "happy" happens, then you still got a massage from a cutie who ran her hands across your body in ways that many guys will never experience.  Enjoy it!

At the least, you should get a HJ with a happy ending release.  Depending on what you agree with the mamasan, more might be on the table.

A table shower is when you are laying on a table and she washes you down with a shower spray, it's nice. What you get depends on what you want, I think.  It all depends on what they will do.

Swim

there are LOTS of Chinese massage places in my area (DC), that are completely legit and do NOT offer even a hand job.  In Maryland it is the vast majority of places you find.
Now you may find a rogue lady in these places (I have), but you certainly shouldn't go in expecting something.

As I've said in my other post, the table shower-type places ARE indeed more of a guarantee (from my experience anyway)

In Houston, you go in and there's typically a foyer with a large board showing their license, an ATM, a video camera a few Asian decorations and a doorbell.  Assuming you haven't made an appointment, a cute little Asian will let you in and guide you to a room (she's typically the one you're getting, I've never had no reason to object).  Walking you to the room you hand her $60 for the hour.  That money goes to the house.  Next you get undressed, some give you a table shower as described with a little attention to junior.  Then you go to the room you undressed in and they give you an approx. 30 minute massage, typically of at least average quality or better.  On the flip you get a cursory front side rub.  Then they will start to pay with junior a little, typically enough to get a rise out of me, then they ask "you like extra?"  Extra ranges from $50 for HJ to $100 for FS.  You can try to give them less, if it's not enough, they will shake their head and say "need more, me love you long time."  Once an amount is agreed on, then it's on.  After, they clean you up and if you request, give you another table shower to wash any oil off.

are there places that you can actually get a table shower where at least a HJ isn't pretty much guaranteed to be offered?
The lady has always grabbed my fella and washed him thoroughly, so I've never had a doubt.  But my experience is limited to a few places in the DC metro area.

where instead of paying the "house" fee and then paying more for "extras", in many Houston, well actually many Texas AMPS, they simply charge you $160 upfront and there is no need to do any further negotiations. Tips of course are welcome, but not required.

I will agree that what you describe is still the standard, but in Texas at least, a good third of the AMP have gone to the "all inclusive" fee.

Also, there has been a huge influx of "legit" massage parlors where you can get a nice massage for a very reasonable price, but NO extras are offered. This also is a relatively recent occurrence, but there are hundreds of the places throughout Texas, many of them have the dead giveaway "Chinese Foot Massage" Not only do these places NOT offer extras, many of them actually have male staffers, and I damn sure am not asking a man for "extras" lmao

Others have already posted that the routine varies from city to city.  I only know the northeast but even there, Boston AMPs (well, there aren't any anymore) are different from Providence AMPs which are even different from NYC AMPs.  And even in NYC there are AMPs and there are Asian Spas that are a little bit different and even legit, no sex Asian massage places!  

I don't know the routines in other major areas like Chicago or LA (see lakstyleblog).  

Try asking on your local (regional) board what the local customs are

 

DANGER, DANGER, DANGER!!  
Not my first AMP/MP by any means but had my first TABLE shower yesterday.  Interesting experience.  I have some mobility issues from nerve damage.  She lead me down the hall...  I was trying to hold onto the towel & my cane, the towel slipped & she said "No bother" threw it aside...  as we were the only ones in there.  After the full soapy treatment on my stomach, she was having me turn over...  I was more than slippery, the table was slippery, nothing to get a grip on...   seemed like I was going to end up on the floor (on my head!)  She ended up drying the table & putting a towel under me for traction.   She's a petite Korean lady but strong as an ox.  Got me sitting up easily.    
However, she said next time I'm going to get a "sitting shower"...  I know I can get safely onto the table for the face down part but need to slide back off the table & do the second part sitting/standing leaning, rather that trying to turn over.  The table is rather high & I don't think sitting on it is going to work (only one hand is strong enough to lift myself with).  

Yes, she encouraged me to "come back any time".    

I'm a newbie.  And I'm in the DC metro area.  Just wondering, any places you would recommend?