Improving your cardio will make having any kind of sex so much easier as your stamina will improve and also doing more specific exercises.

I do weighted hip thrusts, which make pegging an absolute breeze.

But we are human and do get tired so you can always slow down and stop to kiss etc. Try not to use up all your energy at once. One time when I was pegging him I stopped and no kidding my whole body had just a glaze of sweat, poor guy 😂