Season 5: Episode 107: The One With The Inappropriate Sister
Fed up with Rachel's ridiculous mind games, Monica finally asks Danny to go out with Rachel. He agrees, but Rachel soon afterward sees him with another girl. She goes on the date anyway, and Danny says he'd invite her in, but his sister is visiting and she's asleep on the couch. Rachel is relieved, realizing he isn't seeing someone else. Then his sister opens the door and Danny introduces she and Rachel. She is dressed only in a shirt, and she and Danny playfully wrestle while Rachel looks on. Rachel asks Monica and Ross if they ever wrestled, and they say sure, when they were kids. Monica reveals that she was undefeated, to which Ross replies that she weighed 300 pounds. She says yeah, but she was quick as a cat. Monica adds that they don't wrestle anymore, and Ross says that's because she couldn't beat him. Monica challenges him, and the two grapple. Later at the coffee shop, the gang is there along with Danny and his sister. She is eating an eclair and offers a fingerful of the cream to Danny, who sucks it off her finger. Then she drops some of the creme onto the front of his pants, and wipes it off for him. After they leave, the gang is appalled by their questionable behavior, and Rachel decides to end it with Danny. But when she goes to his apartment, he defends his close relationship with his sister, and asks why Rachel is so threatened by it. Just as Rachel begins to soften, his sister calls from the bathroom for Danny to hurry up, the bath is getting cold, and Rachel makes a beeline for the door.