When I was at Uni, I went to one of the society fancy dress parties that was themed "Come as a member of the opposite sex". Almost all the guys borrowed a ball gown from their biggest female friend, and stuffed the bodice with socks etc, and looked just like butch blokes in drag, complete with bluff attitudes and pints. My friend, however, who had long hair and a slighter figure, borrowed some fishnets, a tight top and a miniskirt. He was rather more convincing, to the point of bar staff calling him 'love' and doing doubletakes.
Of the girls, most went as Indiana Jones or Cowboys, which more or less allowed them to wear jeans and a shirt, just like they wore most of the time. I elected to go as a Scotsman, stating it would be the only time anyone saw me in a skirt.
It was interesting, as the evening went on, how the girls started to act more like rowdy men, and the lads started to feel a little intimidated. Somehow, playing characters allowed us to behave in ways we wouldn't dream of normally. I suspect booze 'helped' too.
For the record, no one tried to look up my kilt, and it was bloody draughty!