I think easily the largest percentage of the bleached kink is WMAF/WMAM and my sense of a femboy comes from that. Light skin doesn't really matter to me, but there is an ideal look to a femboy that is simply genetic. That is to say it is based on certain immutable characteristics.
Firstly, they must be short. This can be anywhere between 4'11 to 5'6, but generally they must be smol
Secondly, they must be skinny. The ideal shape of a femboy is the ideal shape of a woman. Submissive and breadable being the meme that communicates the image. Remember diet and cardio.
Thirdly, energetic and pro-cucking. In the sense that once you as a femboy have accepted your role you are now ok with allowing a bull like me to fuck your girlfriend or whoever it is.
Obviously I've known a lot of asian boys like this and some of them have had light skin.