Responses
There's a couple of things that could happen from here,
1.) It could be exactly as you said and that boi McQueen is gonna get his jealous urges and take Tommy right from Lancer ლ(´ڡ`ლ)
2.) A THREESOME which I don't think will be too out of place for this particular manga, but seeing as to how Tommy doesn't REALLy want to bottom, this probably won't happen.

They're being so... vulgar and blunt, Lance just asked for clippers so he wouldn't hurt him when he fingered his ass and he's not rushing out of there. It's... off. The story portrays him as still awkward, shy and a little reluctant to be doing this, but he seems to have no limit to the embarrassment he takes, which clashes with the rest of that. Bottoming was supposed to be something he reluctantly decided to do for money, with a SLIGHT bit if interest in it, but he's sticking with it no matter what. Even in situations of extreme gay sexuality. Shit that would make a gay man embarrassed. It's throwing me off.