Paddy's wife had never had an orgasm, so they decided to go to the Doctors to find out why. After a number of tests and questions the Doctor suggests that Paddy's wife could be over-heating during sex.
Paddy refuses to buy a fan, and decides to get his mate round to waft a towel on them during sex. After 20 minutes of wafting she still had not had an orgasm, so Paddy's friend suggests swapping places, saying "I'll shag her, and you waft the towel"
Paddy agrees, and within seconds Paddy's wife is screaming in pleasure and has the best orgasm she has ever had.
Paddy turns to his friend slowly and say "...... and that my son is how you waft a fucking towel!"