Doing anything sexual in an aeroplane at least a mile off the ground.
As the airhostess passed Johnny he copped a feel of her big juicy ass. She looked around to see everyone asleep and then leaned into Johnny, her big juicy tits in his face and whispered "Would you like to be part of the mile high club?" Johnny nodded eagerly! She led him into the empty First Class area and told him to sit on the bed. He did as told and then she started to rub his cock, the rubbing then turned to licking, which then turned to sucking and the she started humming. Johnny was in heaven! Just before orgasm she took off her skirt and jumped on him and they had the most wild sex ever. A few passangers woke up because of the noise... but they just waited for their turns.