Seth gives Daniel a raised eyebrow at that. He's going to go ahead and assume the 'she' in question is Lucy. And the implication here is then that Peter thinks they've slept together, and Seth wonders suddenly if they have. He wouldn't have thought so, but then Johnny had, to Seth's surprise. One day he should try to get all this from Lucy's point of view, because he doesn't feel like getting so much of his information about her through Peter is very helpful for getting a fair idea of everything. Then again, it doesn't really concern him. (It's probably going to take Seth a while to realise the 'get around' comment might then also imply Daniel's relationship with him is of a similar nature.)