Sex tonight or not

okay soooo me and this guy I've been seeing are hanging out today and have been talking about doing 69. problem is, I think my birth control is messing up and I have literally been on my period for days on end. it's not a lot of blood, really barely anything. anyways, I'm really not into the 69 thing if I'm on my period, but has anyone ever done it? seems messy and really unpleasant.