How Do I Make my Nipples Less Sensitive?

I am 32 years old, I have 7 children and only breastfed one which was number 2 for me. I have such sensitive nipples that any time my boyfriend wants to even touch them I giggle relentlessly. It isn't a turn on to me it just tickles like he is tickling the bottom of my foot!!! I hate this and want to know what to do about it, it not only is bothering me, but him also!!