I am a gay man, but pretty much all of my friends are straight guys; and a lot of my friends I've had for 15+ years so we know each other really well. There are 3 of my friends that I regularly "cross the line" with, but sadly it usually involves me paying them some money ahahaha but I won't go into those details yet. What I've found to be the best method, is to plant the seed in each of their heads the idea that you'd be down to do it, and that you would never tell anyone about it. This is usually best told during drunk moments between just you and the one other dude. For me it's usually been during times when they're asking me a lot of questions about being gay... just like drunk curiousity.. and then eventually I'll throw in something like "Well if you want to know what my type is, it's pretty much you. If you were gay, you'd be a perfect dude for me. Just so you know." And then later something like "So you if you ever feel those urges, just let me know and I'd be down to suck you off or whatever and we'd never have to talk about it again." Usually they will laugh it off, but the thought will linger in their mind for weeks/months until it eventually comes up again. For all 3 of those guys, it's been them that bring it up again, and then at that point I get a little more aggressive now that I know they've been thinking about it. To be honest these are the most fun and satisfying experiences I ever have! Which is pretty sad to say haha but I am really into it.