In reference to fooling around but never fully 'rounding the bases'. Often used to validate otherwise off limits first date behavior as wholesome or clean behavior.
Then Steve said "But Katy, they're only hands...its strictly G Rated"
This is where a young girl is such a whore, she sucks maybe 10-100 dicks, swallows all the jizz, but then later finds out she has had too much to "drink" becomes ill, lies on her back completley naked convulses forward arching her back to her mouth is at her vagina, vomits all the jizz out into her own pussy, becomes pregnant and has a child from it. This bitch would then have to appear on 12 episodes of geraldo trying to find out who her baby's daddy is.
Liora: Oh my gosh. I have a new crush on this guy at school. His name is Brett.
Amber: What's he like?
Liora: Well...he dresses nicely, likes to watch the Food Network, and has Spice Girls on his Ipod...you know, I've never heard him talk about who he thinks is hott though, like other guys do.
Amber: .....so he's rated P.G.?