Like, on the mouth? Where do you see straight men kissing each other on the lips? I don't think I've ever seen that but I rather like the idea.
If you mean like, kissing on cheeks, forehead, hair, stuff like that, I feel like I've seen that a couple times and it is SUPER sweet, and I absolutely love it when they're tender like that. Tenderness, esp between two guys, just gets to me.