OTS means "over the shoulder". In a past post, I talked about how next to the three-quarter angle, an OTS would be most likely be the second most frequently used angle.
I should make a reverse OTS shot for Kassandra, but her hair obscures her torso so any differences from that angle will go completely unnoticed, except for possibly the tears in her pants.
Someday I'll do a profile and back angle, but not anytime soon.