Period Sex

So I'm on my time and in my past relationships was never asked to have sex while Mother Nature is storming around but my new bf and I were talking and he tells me he's really horny and wants sex and I kind of just sat there with a sad look and told him aunt flow was here and he's just looks at me smiles and says babe that's why we have a shower...like I'm happy it's not bothering him and he's willing to do something like that but I've never done this before on my period so I'm kind of scared...lol...what should I expect?? How is this going to feel? Can you guys tell me experiences and give advise please? Tia