can't answer for everyone, but my baby side has a good overlap with my feminine side and it is fun to play in short dresses etc. That said, I don't consider myself a sissy, but it may be more denial than anything else.
Girl baby clothes are soo much cuter than boy baby clothes anyway.
In the beginning we treat all babies like they are feminine….in the way we baby talk them to the way they smell so pretty and feel so soft…it’s not till later that we start to identify boys with being tough and the old “boys don’t cry” mentality…I love my sissy boys 
and it is fun to play in short dresses etc. That said, I don't consider myself a sissy, but it may be more denial than anything else. 