Ballbusting punishment after the beach

My girlfriend and I were at the beach last summer and there was this girl with an amazing ass and such a small bikini
I obviously noticed her but my girlfriend caught me staring at her ass and immediately reached me and whispered to my ear "you are getting kicked tonight"
I took a moment to realise the situation and then I was little scared but super excited as well so I asked her "how many times?" and she replied "10 kicks" and then added "hard"

Immediately when we got back home I started to makeout with her but she stopped me and said "your punishment first"
I followed her orders and undressed, then she placed behind me and spread my legs
She didn't kick immediately but she started to play with her little foot beneath my balls, my cock was already rock hard, anche then BANG she hit with the first kick
I drop on my knees, this was a good hit but she ordered me to came back on my feet
Once I was back she mocked me saying "I've seen you staring at that girl ass and now you must pay the prize" and as soon as she finished the sentence another kick right in the middle of my legs.
The punishment progressed normally until thw last kick... she was playing again with her foot against my sore balls and then told me "I want you to be prepared for the last kicks because this is what will happen if I will catch you staring at other girls ass again. Do you understand?" - "yes miss" - "Are you ready?" she said, "yes miss"
And then hit me with the strongest kick i have ever received.... drop on knees and reach for my swollen balls while she made my kiss her feet....

After that we had sex but I didn't manage to endure more 10 minutes because I was to excited from what just happened and I even told her "if this is what I get I will probably to it again" but she grabbed my empty balls and said "next time I will hit way harder to make sure it won't happen again"