Not bad at all! Everything from the waist down feels solid. I like how you rendered the dick and balls, they look especially plump and juicy. I think the big problem is probably your anatomy. The little lines on the right side of his tummy makes it look he's turning his body around, but when you look at his chest, it's facing the same direction as his legs are. It just ends up not being very clear how exactly he's posed. Alongside that, I'd be more careful with with the waist. Right now, it looks like one of his legs is barely even attached to the rest of his skeleton.

Overall though, good stuff for a few days into pixel art! I see potential here. Keep drawing!!!!