Agitation during mindfulness tickling

I was following [an older thread](https://buddhism.stackexchange.com/q/17341/254) , however I would love if someone could respond with an answer as to how I can handle the following situation. This happens almost every time I do mindfulness. As I sit in mindfulness I almost always get a tickling or tingling sensation from my clothing, whether its the bra or underwear etc. As I sit there I try to continue breathing in and out focusing on my anchor, but inevitably the sensation gets the best of me, I feel exasperated and do what I ned to do to relieve the sensation. I feel like I could burst from the agitation sometimes, and I have never been able to sit through the agitation long enough for it to go away, the agitation can persist for 10 plus minutes.