Masterbation in the Shower?

I’m currently a college student and I try getting off in the shower; however it’s difficult to do it standing up. I have a bathroom in which I share with 2 other girls. Laying down seems sketch to me but not sure which would be better. I have a hard time sticking my vibrator up my vagina but I’m working on relaxing more. Does anyone else do it in the shower? And if so, what position is best, if you don’t mind me asking?