It's bad to be attracted to your siblings.
Ash is hanging out with his best friend Thomas, and Thomas is making comments about his sister's body.
Ash wants to gain Thomas' approval.
Ash offers to set Thomas up on a blind date with his sister.
Ash agrees with Thomas' observations while adding his own comments about his sister's chest.
Thomas and Ash's sister fall in love during their date.
Ash's words make Thomas feel uncomfortable.