Consume it for three days leading up. And clean out your diet. If you're eating lots of red meat, drinking pineapple juice won't do much. Same with if you don't eat many vegetables or LOTS of salty food. It's not enough to just drink it a few hours before, you're trying to change your body chemistry, here.

This is much easier: right before your next bbbj, stick your dick in a bowl of sugar and tell her to pretend that it's a cream-filled eclair