Pegging, in the most basic sense, is the practice where a lady (equipped with a strapon dildo) has anal sex with a man.
This basic description doesn't do the practice any justice in terms of how hot, kinky, and liberating it is.
Pegging is a full role-reversal, where ladies practically top and the men practically bottom.
I am of the opinion that every open-minded couple, and every progressive lady, should experience this at least once. So much so that I offer my services to help you experience this.
Message me if you have any questions, or are interested in taking me up on this.