Quote by Barney Stinson from How I Met Your Mother in Season 5 Episode 1

"How do you keep a girl from becoming your girlfriend?
1. Never get them wet. In other words, don't let her take a shower at your place.
2. Keep them away from sunlight - i. e. don't ever see them during the day.
3. Never feed them after midnight. Meaning she doesn't sleep over and you don't have breakfast."

Quote by Barney Stinson