'Hand over mouth' - Reason for rape
This would explain that hit seems he did coomit a crime, however she said he lets all her boyfriends do that. I presume John was the first, either she was joking which makes sense although disturbing, or she enjoys it, or having had John do it, was afraid, we are led to believe she abstained from sex for a whil, maybe afterward she asked the guys to put their hand over her mouth, to help stop her from crying or panicking.
Or perhaps she didn't want to scream (with orgasmic joy) whilst with John when they were doing it?
"this is it" "chew some gum your breath smells like my grandmothers feet" THE CHASE