Silly Stardust. Rocky’s mane isn’t chocolate. Tho it kinda does look like caramel chocolate
Anyway, I like to think that Stardust would see Rocky as an older brother in a way. He (presumably) is good at playing guitar, she’s skilled at ukulele (which is basically a smaller guitar) and they are both pegasi who likes music (with different preferences mostly, I guess)
Also, she tends to playfully tease or give nicknames to characters I really like (or fixated on)