A PAIR OF SHOES

I won't beat about the bush. I went down town for a new pair of shoes straight into a gay pride march. Fighting my way through the crowd I found myself nearing the shop. I just needed a minute and ducked into a alley where a man got me naked and gave me a blow job. I was placed on a filthy tarporlin naked my legs left to there own devises his hands lifting my bum my cock in his mouth and me shocked wondering how this had happened. He was weakening and as my hips lowered my cock fell from his lips. I was by now so horny that I placed my feet on the ground and lifted my hips to allow him cock sucking access. He blew me until I nutted, swallowed then stuck out his tong I guess to show me my cum had gone. He wanted me to blow him too but I refused. At that point he got up and left me there naked minus a load.
Question;- Should I have sucked his cock as a thank you, it was a really pleasurable and an experience I'll never forget.