The girls were looking for fun, riding in the car. Sometimes they got themselves excited. Apparently they wanted a new sensation, so they offered a threesome to a strange young, handsome guy. After some persuasion and conversation, he agreed and went straight to work. The girls hooked up with him, gave him blowjobs, rolling on top, while two were fucking, the third fondled the couple.
A lot of girls wouldn't mind getting that kind of medical care! But they just don't meet these doctors, and they are too embarrassed to ask to have it added to their medical records. Look at the fervor with which she is treated in the 9th minute of the video, I even wished I had gone to medical school myself.