LorienLlewellyn
You are definitely not obligated to do that with him no matter how much you care about him or how good of friends you are. You have no reason to feel guilty for turning him down. If he ever gets mad at you or stops talking to you for turning him down, then he isn't actually a true friend anyway. True friends don't pressure each other like that.
Unless he has his girlfriend's ok, he shouldn't even be asking you that in the first place.Wildflower Euphoria
He didn't pressure me at all. he just sort of suggested it. As Lorien said, even if he "just suggested it", unless his girlfriend is ok with it, he shouldn't even be bringing it up.
I went down this road with a friend of mine a few years ago, and it turns out he was having issues with his girlfriend at the time (which I didn't know about). Maybe your friend is having issues with his girlfriend, in which case if he admits to it, you could encourage them to talk things out.