early days of aviation
Whereby a male dons a leather cap, scarf and aviator goggles, pulls down his
breeches and underwear, stretches his arms up in order to grip an imaginary propeller, and then procedes to jump up and down causing his flaccid penis to
girate very much like a propeller in the early days of aviation. This delightful party trick can also be performed by women, whereby rotating breasts serve to represent said propeller(s). As described by one S.
Milligan of Monkenhurst, Hadley, some time after WW2.