Period sex?

I'm seeing my boyfriend tomorrow and my period thought today would be a great day to start. 
We have tried having sex on my period before but it was uncomfortable and messy, so we didn't try it again. 
I really want to try it again though, as we haven't seen eachother in a few weeks and my sex drive has been quite high. 
Is there any tips or things we could do to make it easier? 
Shower sex is a no-no, as my shower is incredibly small. 
Thank you.