A childhood belief about rude bits

After having been given "the talk" by my Mom at around age 8, and given a picture book (*ACK* I don't yet know how I'm going to deal with this with my kids, but I don't think it'll be via picture book!) giving some of the (very few) details of baby-making, it never occurred to me that a boy's privates got firm in order to make the "grand entrance." I had seen only my father and a baby cousin naked, so I always had this idea in my head of grown-ups doing strange contortions in order to slide the very limp member into the girl's private area. So it was with blissful innocence I that I just smiled when, in middle school, some of the boys in my class teased me about another classmate getting "hard" after I had naively run my hand through his hair, just the way I had with my younger cousins... I had no idea what they were talking about, and I was quite shocked (and somewhat relieved) some years later when I discovered that that wasn't exactly the way things were done. :O)