I don't understand why it's not "Kicking the crotch in a guy", isn't it "kicking a guy in the crotch". Please explain about this.
"Crotch" means the genitalia of the individual. "Kicking a guy in the crotch" means to kick someone in the genitalia region. "Kicking the crotch in a guy" isn't used because of the word order sequence. English can be fairly inflexible and follows specific word orders. "Guy" in this sentence is not the subject. The subject in the sentence is "crotch." "Guy" is being used as an adjective to describe whose crotch is being kicked. You can't "kicking the crotch in a guy" because the crotch doesn't possess the guy.