Cross dressing can sometimes be temporary but taking on more manarisms and every day things girls normally do is sissy where it is not just dressing
Example: a male cross dressing as female knowing they are still male is cross dressing. If your curious on this in Japan it is referred to as otokonoko or “male daughter” in Japan where one is usually treated as a girl knowing they’re still male but dressing as female
Taking on motions, activities, actions, makeup, enjoying more of the kawaii life, and believing they are a girl deep inside is trans/sissy sissy’s are more likely to make the rest of their body be more like females not just with clothes. This includes accessories, voice training, scents and perfumes, etc.
A test of this to see which one you are is asking why you do it. If it is feeling like “it is who you are and meant to be” it is possibly sissy, but if it is something you do every so often or for a “quick fix “ it most likely is cross dressing only
It is possible to have one, another, or both. Fantastic question, so really think how do you feel when you are acting that way? Really dive into your emotions