Master Double Jet.

It's a common meme to mangle Twin Turbo's name (into Double/Twin/Dual/etc. + automotive/aeronautics engine-related term). Or call her Master (in the master/apprentice sense). Both often occur together.

(Anime Teio also calls her Master after Turbo helped lift her out of her funk.)

Same goes for the original memehorse before Umamusume even hit.

(Think Smart Falcon also gets called "Master..." too by horsefans, though not in Umamusume.)