Guess this can be answered both by hobbyist and providers. Seems a little counter intuitive but sexual activities you won't do with providers/clients but will do with partners IRL? Kissing? Greek? Etc etc.

is a 3some. It's something that I enjoy immensely with providers but I'd never try to talk my SO into trying it. I'm afraid that she wouldn't be down and then when she turned me down she'd start getting suspicious of my asking and she'd start wondering what I'm up to. As much as I'd love to try it with her, it's just not worth the risk of asking.

I tried it with an SO once and she had so many rules it was clear she didn’t really want to do it and didn’t really want me to do it. Other SOs have preemptively prohibited any mention of it.

on the subject of threesomes.  At times when I have girlfriend, she knows I'm into P4P, but to involve her would be more trouble than it's worth. Better to do it with two providers.  The difference between you and I is mine would have an M, me, and not three F's.  Lol

that comes with a GFE session with a provider, so I generally eschew activities that require advance notice and preparation, like Greek, but some of the girls I see in London are always prepared for anal for every customer, so I can decide while I'm there as the mood strikes me.  Other activities that involve heavy equipment is a no for me at a paid session, as well.  I'd rather set up the room in advance with everything I need to give my sub a breathtaking experience, then go to dinner, and come back for playtime, which is harder to do with a professional, so I limit this stuff to real life sex partners, usually at their request.

Heavy equipment? Please do elaborate

in order to move his giant wang into position. This requires a dozen heavy equipment operators.

I was talking about bondage equipment, but I think you know that.  Good one, though, you got me.  

Like I said in op, I'm pretty vanilla so no I never even thought about that type of equipment