I just plop it on a convenient level surface whenever there's a pregnant enough pause in the moment (maybe after the greet, or while I'm getting dressed if I didn't do it earlier). Well, I lay it down easy, not a clunking, 'THUNK' or anything.
Some of the new girls reach their hands out for it, or even ask for it. I try to edjumacate them with a head shake
and/or say don't give a UC the satisfaction. Sure, they can bust you anyway, but don't give them any layups. Let the guy sit the money down. I know you want to make sure he pays, but that doesn't mean reaching out for it. It's better to give away some free pussy than to fall into a trap.
I don't bother with envelopes, either. It becomes a wasted step, IMO, not to mention being a chance for a dirtbag to skimp out with a couple bills on top and fake money/paper underneath.
All of this is conjecture for me anyway, since I'm so ruggedly handsome, built like a Greek god, and have the perfectly sized dick to please all women, because they slip the donation back in pocket before I leave.