1. To smoke herbs in preparation for a competitive event or in celebration of the victory of a competitive event
"Bro, that was an amazing match, I am going to be Phelpsing with the good stuff tonight!"
Getting super H and go swimming in a pool.
Guy 2: Ya, after he took all those pictures of himself ripping that steam roller he's been doing laps at the Y.
Guy 1: Man that guy's all about Phelpsing.
Guy 2: I can't believe you used that word you tool.