28[M4A] Indiana/Online - I can’t stop thinking about my GF wanting a “threesome” that’s actually just an excuse to see me get fucked

It’s a fantasy I’ve been having for a while now. She wants a threesome with another guy or girl, but when it comes time to, they turn on me, with them completely dominating me while she watches. My cock throbs every time I think about them demeaning and insulting me as I squirm on a thick cock or strap.