Pegging means a woman penetrates a man anally, usually with a strap-on dildo. For many couples it is about role reversal and trust more than about dominance, though in femdom clips both often go together.
In clips you will see it as part of a femdom scene, as couple play, or as instruction videos. Good creators talk about preparation, lube and pace – which says a lot about how seriously they take their partner.
Back to the clips.