/cgl/ - Cosplay & EGL

Kind of personal but I want to ask /cgl/. I have a gf, she isn't hugely keen on satisfying me in every which way I ask but something I want to do before I die is have sex with a cosplaying or dressed in lolita gear. I just want to know how I should ask her if anybody here has advice?

Is there a way for me to size down a long purple jacket that i bought at a thrift store that's too big, yet the perfect shape and price for my Purple Rain costume? I'm going to mod it with studs on the shoulders
Can post photos if needed. It's a thin sort of slick material, but wanted to know if any of you fine people have experience with making long coats smaller ^_^;;