One-track mind

I need to get a birthday present for a teenage boy, so I've been doing a bit of armchair shopping here - which is how I came across this DVD:



And the first thing I thought was "what's a fertility video doing in the 'suitable for teenage boys' section?" - but then I figured out that 'follies' in this context didn't mean 'follicles', and that 'NFL' probably doesn't stand for 'National Fertility League'.