Boobs, butt and crotch ultimate attack
It looks like the redhead is trying to hide her very unfortunate case of cameltoe by slamming her butt into Inglis' back which is causing her to lurch forward.
She must have learned from how uncomfortable that outfit is because in the anime, she wears pants.
(Cover of Reborn to Master the Blade: From Hero King to Extraordinary Squire #3 manga by Moto Kuromura, published by Hobby Japan)