Jebens1 :
From the chapter Turf War of Equestria Ninja Girls: Forgotten Friendship.
Leo’s beach wear by BozzerKazooers (>>1957543)
Equestria Ninja Girls: Forgotten Friendship by DarkMagicianmon a.k.a Wildcard25.

In that version of Turf War, instead of Applejack, Timber completes with Leonardo to see who’s the better life guard. And just like in the short, Leo and Timber work together to save Bulk Biceps. Then afterwards they race off to their next rescue. After they leave, it’s revealed that Twilight Sparkle staged the whole rescue, to which she explains to Karai and Sunset that she didn’t like them completing each other and had Bulk pretend to be in danger in order to get them to work together. Then Pinkie Pie teases her “that she was looking out for her two boyfriends.”