Perhaps by their own twisted definition you could call it lovemaking - but I would describe it as something else much darker.
At least Sho tried to make some sort of amends and seems willing to talk once Jun recovers, but Jun has to stop allowing this. Even while it was happening he knew it was wrong, but seemed powerless to stop the same scenario playing itself out again.
Jun is going to be in so much trouble with Toshida-sensei for sliping backwards like this.