Contingency has good concepts for porn. But there's just something about the art style that's incredibly off-putting imo.
Also yea what BlackIce211 said, there seems to be a theme with this collection. Not judging you for it, but it might be a good idea to make the Gallery Title reflect said theme.
He draws the ass like it's a baloon grafted onto the leg. All he needs to do is like take 20mins to study how the muscle flexes and changes shape with movement and he'll be good to go.