Guys used as an example to train other girls

One of my favorite type of BB story is when a more assertive girl makes a guy act as a prop (either with threats of worse harm/consequences or promises of getting laid) for an inexperienced girl to learn about male anatomy for pleasure and for pain/control

Would love any stories falling into this area, especially love if there is a shift in dynamic where the guy once underestimated or felt protective of the girl only to leave the experience terrified of her

One example of that dynamic that I’m blanking on the name or author had a guy bring have his coworker and her bf over to share how his girlfriend uses ballbusting in their relationship. He thought he was helping her relationship with her rude boyfriend but by the end realizes someone he viewed as an equal colleague now holds power over him. But can also be fathers or big brothers learning to be scared of their daughters/sisters who used to look up to them