I've been seeing a girl for 3 weeks and our relationship is very much sexual at the moment, we can't keep her hands off each other! She told me she was on her period last thursday so I said bloody hell that's a shame, no action for me tonight! She replied "what!? doesn't affect anything we do! sex is better on my period, tastes better as well". I asked if that was a hint for me to go down and she said if I wanted to I could. Anyways I did the deed and couldn't tell the difference, I only stuck to the clit and didn't venture inside though! Spoke to my mates about this and they were horrified and disgusted. so answer to your question is I think its a very small % of guys that would, I think its also a very small % of women that would let you.
I never have had any limits/boundaries, ill do anything. lol