"putting on his mothers clothes" Well, yes, that could be a starting point, a may be a game of dressing up with sisters or friends, Party games, forfeits and or Halloween Fancy Dress.
boys can dress as girls. It is not socially acceptable but it can be done. I believe it need to be done more often so that it does become acceptable you never know if one boy does it that may give...
The most striking would be the item that could not be seen as unisex.The Dress, the most feminine identified item of clothing, the more flowers in the pattern the more lace in the design, the full...
you will have to get a girl that is going out with a boy and the boy does whatever the girl says then you ask them if they can tell their boyfriend if he can dress up as a girl
Well, different girls like different things. Personally, I think girl-like pants are okay as long as it isn't obvious like butterflies and stuff. A lot of girls think a little guyliner is a turn on....