Where did that practice come from, and what does it mean?
I’m not an athlete. Poets don’t do that. 
Peace,
mangeorge
First time I saw it was with Jesse “the body” Ventura. It means I got huge biceps and I love them.
I think that’s where I first saw it too. Also Joe Montana, Colin Kaepernick, and others.
Oh yeah, the WWF dude with “pythons”.
Colin Kaepernick is more specifically kissing the tattoos on his arms. As he was becoming the starter in San Francisco, some idiot newspaper columnist wrote an opinion piece about how shameful it was for a role model quarterback to have visible tattoos, which only criminals have. The kissing move was Kaepernick’s response. His tattoos are all biblical references and verses.
Was that before or after Thunderlips The Ultimate Male?
You poor poor man, you obviously didn’t get your tickets to the gun show.
I could host a very small gun show of my own, which seems to confound many conservatives. 
“Kaepernicking” is the current usage, as based upon “Tebowing” and similar QB trademarks.
I wonder how old the practice is. I remember a friend of mine doing it back in the mid 80s.