What is Benadryl Challenge?
The act of taking a normal or slighter higher than normal dose of benadryl and attempting to masturbate. The usual rules include a 10 minute buffer to allow the pills to start working. One loses the challenge if they fall asleep before orgasm.
"Man, I tried the benadryl challenge with 6 pills yesterday, but I passed out cock-in-hand in front of my laptop with asian porn on."