Tight clothes make his brother get hot very quickly
Wear something comfortable and then start exercising, it makes sense. It’s what people do when they want to exercise, since that makes it easier to move so they can stretch and all that shit that people do who want to live a “healthy” life. Although in this case, it may seem the same, but it is not. She wears tight clothes because her brother gets horny very quickly when he sees her dressed like a whore. Much more so when she grabs her pussy and offers it to him. Then he has to put his cock in because there is no other protocol for those cases. It’s the most normal thing.