First Base, Second base and how I get into odd conversations with the Girls

Several weeks ago the girls and I were in the Palisades Center and Nastia asks me if I would really buy her and her sister t-shirts that said 'Guns don't kill people, Dads with Daughters do' when she has a boyfriend. And like any red blooded American Dad, who was young once and knows what goes on said of course I will. I will let them get to first base, but they better get thrown out if they try to steal second. For a second I forgot my audience and they ask me what is first base, and second ... I point at my lips and say first base, then at my chest and say second base. There my courage deserts me and I point toward the ground near my feet and maybe as high as my ankles and say third base. I don't talk about home.
   Elena, always a little more in tune with things that concern sex, which scares me, says third base is the va-jyn-ya. And then I say with all good grace that home is sex and they both get a good laugh at it all and then they ask why is it called first base, second base ...