Two become three

Mia Cheers and her boyfriend come to the private lesson to improve their English skills. The teacher gives them a little test, which they should finish within 15 minutes, and leaves the room. Mia Cheers knows she needs to focus on the test, but she chooses to seduce the lad sitting next to her. He tries to resist her attempts, but then surrenders to her and gives her the doggy fuck that she needs so much. Little do they know, the teacher spies on them for a while before joining the fucking couple and turning the duo into a trio.