Does have a slight style issue in that Jasper has a different design than Lapis. Its like they are made with different anime-esque designs. It's not too distracting. But they don't seem made by the same artist. (Primarily the eyes and mouth)
Aside from that, there's some issues with Lapis's buttocks , along with lacking an anus. And her gem seems to be slightly out of angle.
As for Jasper, giving him a stylized dick looks pretty well. As with most of your genderswaps. He's not as hyper as most though. Almost proportionate even. His balls transiton a little weird though, curve wise. But otherwise most joints look pretty good.
If you put like, 20 % of the effort you put into the dudes orgasm, your claim that they have simultaneous orgasms would be a lot more convincing btw. Actions speak louder than empty words.