Contractions feel like menstrual cramps!?

I find it amusing when ever I hear that. Maybe it's because I don't get menstrual cramps very often but I feel sorry for those who go into labor thinking it's only going to feel like cramps lol then I'm thinking they must have some really crazy cramps to compare the two! 
My contractions were nothing like menstrual cramps. If I was describing it to anyone I'd compare it to having your uterus slowly twisted for 30secs and then released for a min before twisting again. And if it was a man I was describing it to, I'd just substitute scrotum for uterus!