My ex always claimed her nipples were wired directly to her clit. She could actually cum from pinching her nipples. When she was really hot she would order me to bite her nipples hard (just short of drawing blood) which gave her a massive orgasm. After she was fully gratified she would let me fuck her sloppy wet cunt.
a lot of women have a direct nerve connection between their nipples and their pussy! Stimulating the nipples causes shocks to go to the pussy... making it contract and ache... every woman is a little different so it's always interesting to discover how a woman is wired!