He's probably fine, he probably just finished up marking his territory by rubbing his...erm... junk around lol. If he's still acting normally then I wouldn't worry.
Thats fine. As long as its not like a constant thing, as if something were bothering him. Sometimes they like to fancy them self a little...if that makes any sense.
As long as he's not doing it 24/7 he's fine. Its a perfectly normal behavior for healthy male leos. I've caught my male doing it 3-4 times in the past 2 years.