Is this odd?

ok well the other night me and my gf were walkin around town and i was holding this bag...i swung it around and hit her in the back..(the bag had clothes in it it was soft and i barely knicked her) anyway she got rily excited and we started flirting and stuff..well then she came up to me and smacked my ***....i found this to be very hott....so i smacked her ***..she must of too bcuz this kept going for a while....it didnt lead anywhere and i didnt want it to..i'm to young for and stuff like that...but do u think thats odd that we both enjoyed doing that a lot? or that we both just even did that?