My bra is to tight

My bra is to tight and I am to embaressed to ask my mum for a new one could you give me some tips on how to ask.

ANDY'S ANSWER: The best approach is just to be clear. Your Mother will understand the issues if you have outgrown your bra. It's no different than if you've outgrown any other clothes like your pants or shoes.

"Mum, can we go bra shopping please? This one is getting too small for me and is cutting into my back."