Horse riding

It was a Friday afternoon and Salim and I were at the beach enjoying a good dip in the ocean when Salim noticed horse riding going on. He is fond of horses and he took a ride on the horse. I too took a turn to climb up when Salim urged to try for once. The animal felt sturdy and strong. My first time on the horse.. A bit scarred but excited. I rode a circle while Salim advised to try running faster as that's were the whole game is... Having done the first ride okay I was confident nothing much could happen.
Until I said OK.
Salim whacked the back of the horse. It made some wild scarry sound and rode fast across the beach. I was all jingling the way to and forth and noticed my breasts has jumped out of my bikini. My hands were glued to the rope and oh my god my breasts were so wildly shaking. The master whistled back when the horse slowed down and it's started walking back to its master where Salim too was. I wanted to rearrange my bikini but I was frozen. My hands were like glued to the rope. While it walked back through the beach in front of the the beachers, whistling at my semi nude posture. Salim was laughing seeing my cry.