Cute, but curious

Here's an interesting situation I encountered last week for the first time during an art college class in 23 years of modeling. The students were studying foreshortening, so I was in a reclining pose and some of the students were position at the end of the posing stand where my head was and some were where my feet were. after the 20 minute pose, I got up, robed and began walking around to stretch and check out how the students did, as I usually do during my breaks. I came upon one of the male student's work and noticed a "smiley face" drawn were my genitals should have been. My experinece with young students is that sometimes they get silly and put funny caption bubbles above my head or position me into some wild locations, such as a bar or deserted island, but this was a first. I admit this young man was sitting directly centered on the pose, about 4 feet away and everything I own was exposed to him. I could have been just too much, although if you check my photo file, you'll see I'm not very "intimidating." ;-)Anyway, I just chuckled and walked away with a smile -- on my face. But this does lead to the question, how many young students avoid capturing the form and shape of male genital in long poses? And are female students more likely to avoid drawing them than male students, or vise-versa?Any comments or viewpoints on this anyone?