Newbie strapon/ period advice!

Hey Everyone!

Thanks for all youI help in advance!

Me and my girlfriend are looking to introduce using a strapon (me top, her bottom) and she's been waiting quite awhile (as I've been putting this off). I'm finally ready to give it a go and she really wanted to go into the New Year this way. Problem is.. I'm now on my period, so I was hoping anyone would have any advice on

1. Should I be worried if I'm going to put the harness over my underwear?

2. This is my first time and she kind of expect me to be good (due to our dancing actions lool!)

3. I'm asumming doggy would be the best position as we're known for our "daggering"

I don't know but New Years Eve is tomorrow and all advice would be helpful! Xx