Revenge sex with theif’s GF in McDonalds playground. [m/f]

So this happened quite a while ago when i was a young and reckless youth. I was hanging with my mate and was about to go smoke weed with his friends (who i hadn't met) so i was trying to be real nice and even shouted one of them a drink. We get to smoking and turns out it's legals which really fuck you up, being my first time on legals i end up greening out (passing out) and wake up about 30min later with $40 missing from my wallet. Not long after one of the group members returns having shouted everyone maccas even though he's known to be a cheapskate with no money. I accuse him of stealing my money but he denies it and runs off.