I have to discontinue the use of pull-ups.

I noticed this week that DS gets little tiny fuzzy strings wrapped around his penis from them. They're so thin that you can barely see them. Last night it completely freaked me out because he was realy cranky and having these crying fits and I couldn't figure out why. Then I thought I'd check if it happened again and it did. Has this happened to anyone else? I believe it is coming from the feel and learn. But I'm so freaked out that it might have really "hurt" him.