"Supaman that ho" means to ejaculate on a girl's back and then stick the sheet to it, so that when she wakes up, it's stuck and she looks like she has a cape on. It's a pretty common term, been around long before Crank That came out.

Soulja Boy told some DJs exactly what the song was about and there's no sign of him being confused about what a bitch or ho is, or what superman a ho means.