When a strong virile man has a cock cage on possibly with a leash on at a couples fetish party. His strong woman is holding the leash. Like in a Stag/Vixen relationship.
The mental image is similar to how a rich person would show off their pet tiger. Instead a woman is showing off a large powerful man with a large cock. The implication is that if you are nice to the woman, she might let you pet her tiger/play with her mans cock. Tiger in a cage/Tiger on a leash
She has that tiger on a leash. She has that tiger in a cage.
When one of your friends got a new gf and you are rearly seeing him anymore. A girl who got his schedule under full control and he wont resist.
Dude, where is Frank tonight? We were supposed to meet for drinks!
Ahh you remember Amanda, she got his balls on a leash for good now!