Shower Sex + Other Positions

My boyf and I have tried shower sex but we can’t seem to get it right. We’re about the same height, so I don’t know if that’s why it’s so difficult or not. Any advice on how to give it another go?

Also, any advice for feeling comfortable changing positions up? If I haven’t been drinking and don’t have that courage I find it so awkward to be in positions outside our norm. Any advice for spicing it up without feeling so uncomfortable?