I'd practice having sex
Okay additional rule. It can only be something that you can do by yourself.
solo masturbation =/= sex
Ok fine, I guess I'll stop shitposting. Although I had a couple Pornhub videos I could have posted if I was feeling snotty.
Fuck, I want to say Krav Maga or Jeet Kune Do but any fighting stuff really needs another person. I guess I would choose carpentry. Solid skill to have, good economic and household applications, makes a nice hobby, too.