Caress Wifes Anus

My wife and I have only had anal a couple of times because of a bad experience many years ago. Recently however when we have sex ive started to caress her bum hole just when she’s ready to cum and I have found she has huge squirting orgasms
I want to fuck her arse again but she’s too embarrassed and won’t let me
Does anyone have any advice on how to convince her it’s a great experience