Hi M.,
With the bed wetting, many kids have this problem, and will out grow it eventually. Age five is not that old for kids who are having this problem (although most kids without it are dry at night long before this age) so for a child who has this difficulty, he could take several more years before he will gain control, but it does happen. You can talk to the Dr, or you can wait it out and use good nights. If you have not had any luck with the standard things like limiting fluids at night, there probably won't be much else you can do to help him until he matures. I know kids who have gone until age 12 with enuresis, so he is not that old in terms of the issue.
On the other issue, you should seek help, but I am not sure what kind of professional you should seek. It sounds like you are baffled about where he might have seen this behavior, it seems a little overboard for the usual hands in your pants kind of thing with boys. You might consider asking your pediatrician for a referral to a social worker. Maybe they could set you up with the right kind of professional who could get to the bottom of where he was exposed to this, if there is anything, or help you get some help to get it under control.
If you think that he really does not get how relationships work, as long as there are no other social oddities then you can probably assume that this is behavioral, but if he has other social difficulties, language, sensory or attentional issues too, then you should look deeper into a developmental evaluation. Bed wetting frequently accompanies developmental delays.
Good luck
M.