The Wonderbolt’s locker room was often filled with horse play after training and shows as it was the time that the Wonderbolts could start to unwind.  
Since Dash joined the Wonderbolts, the amount of pranks and jokes that occurred during this time increased. No pony was off limits to her pranks and being in a unisex locker room, the stallions were often prime targets.  
While Soarin wasn’t paying attention, Dash gave him a wedgie and managed to hook his underwear over his wings, giving him a wing connection wedgie.  
Though Soarin wasn’t hurt apart from the hit his dignity took from having a mare wedgie him, he plotted how he could get back at her
 
Alt FA source: http://www.furaffinity.net/view/24705095/