I don't think Phil realizes he's grandstanding in his speedo. Chicks dig his little tight ass.
"Showing off" or going out of one's way to appear spectacular. See showboating
"After jumping the grand canyon on a unicycle, Harry was grandstanding by cycling backwards with his eyes closed with his underpants on fire."
To perform , show off.
Look at dude over there grand standing tryna impress allison. pshhhh
To receive fellatio while defecating in the upper tank of a toilet instead of the bowl.
"John keeps talking about how he got a lumpkin AND upper decked somebody the other night."
"Nah, he was just grandstanding - "
Brilliant persons of an upstanding community. Usually with huge bottoms.