maybe you should teach me, i need a ''how to approach a str8 dude for dummies''
For myself, there are 2 types of straight guys:
1. The ones who
are straight, but given the right scenario might allow a trusted bud to go a little further. For instance, a co-worker that they've become close to, gone to hell and back with, who they know is gay. Time, horniness, and maybe some alcohol, really loosen up the odds they will let you blow them. No kissing, no bodily contact, no clinginess, and 100% ironclad discretion. But, even if you do get to go there, there is no guarantee afterwards that it will happen again. In fact, they may be scared off and your friendship will end.
2. The ones who are deeply closeted, and give all appearances of being straight while also having a gf/wife and maybe some kids. These guys are tricky, or very easy, depending on if they are afraid of being caught, or have had a little more experience playing outside their relationship. The easy ones can be a little slutty, but you still have to be respectful of the illusion they maintain. You may know, they may play, but chances are their significant others are clueless.
The more closeted, fearful ones, are tricky because they very much have two warring personalities. I met one who was repulsed at himself, and other gay men, yet there were moments when his inner self popped to the surface. These are the types that can get violent, especially if you get to blow them, or fuck, as after they shoot their load all the guilt and self-loathing comes out. Best to stay away from these people, as they are very unstable.
There isn't a playbook like with gay men in a cruising bar. For the most part, you need to get in their inner circle, and it is a genuine friendship. So, on that note, you need to weigh the benefits of taking a potential opportunity with jeopardizing that friendship. The sluttier closeted guys generally have been there done that, often on Craigslist or in a porn theater. The latter can be risky as sometimes having spur of the moment anonymous sex doesn't involve condoms. If they are in a sexless marriage, they will be less concerned about contracting a STD.