Head Boarding

A form of Sexual Asphyxiation you go down on your partner (Head) while they stand in the shower and water runs along his or her penis and water (Boarding) you while you pleasure him or her.

"You pair are always at it! I didn't mean to walk in on you head boarding her last night"
"I heard you and your boyfriend in the shower last night."...." Yeah, I totally head boarded him, but he loved it".