heres a transcript of the scene i found it online
Danny: I had a really nice time tonight.
Rachel: So did I. I'm really glad Monica asked us out.
(He kisses her.)
Danny: I'd love to ask you in, but uh, my sister's visiting and I think she's asleep on the couch.
Rachel: You're sister? You're sister's asleep on the couch? (Danny nods, "Yes.") Ohhh! I saw her with you on the subway and now she's asleep on the couch!
Danny's Sister: (opening the door) Oh, I thought I heard you.
Danny: Oh hey, great, you're up. Rachel, this is my sister Krista. Krista, this is Rachel.
Rachel: Hi!
Krista: Nice to meet you. I wish you'd told me we were having company, I'd fix myself up!
Danny: Like it would help.
Krista: You are so bad! (Hits him softly.)
Danny: You are! (Hits her back.)
Krista: You are! (Hits him softly.)
Danny: You are! (Hits her back.)
Krista: You are! (Hits him softly.)
Danny: You are! (Hits her back.)
Krista: You are! (Hits him harder this time.)
Danny: You are so dead! I'm gonna get you.
(He starts chasing her around Rachel a couple of times before she runs into the living room and he tackles her on the couch where he starts tickling her.)
Rachel: (not sure what to do) Uh, it was very nice meeting you. (They continue to ignore her.)
Commercial Break