I've noticed that whenever I am standing, say next to a kitchen counter or when I'm at the sink brushing my teeth, I have a tendency to lean in with my crotch resting on the edge of the work surface. This provides me with additional balance, it's like having a third leg.
Since I've become aware of it I've been trying to cut back and also watch out for other people but as yet I haven't seen any fellow crotch-leaners, so the question is are you out there? Did you notice?
*adds "tables" to internal "things to never google for without safe search on" list*
Can't say I have a habit of putting my junk on random pieces of furniture. I do lean on stuff more than I probably should, though. Using my hands and arms, mind. My peepee is a (most of the time) soft and vulnerable area, so I wouldn't dare push it against anything that isn't a consenting female. It is not designed for supporting my weight.
Also: What if someone kicks the table while you're rubbing your junk all over it? Not a risk I'm willing to take.
As a guy, I can orgasm by doing that, for some reason. Pushing up against hard things was basically my masturbation method as a kid before I discovered how you're supposed to do it.
Maybe for that reason, no, its not a habit to lean against tables.