Twilight Sparkle still doesn't understand a lot of things about the human world. Like swimsuits, and the fascination with breasts.

Even in Equestria, she's a virgin and doesn't really have much experience in sexual matters.

Sunset Shimmer takes it upon herself to give Twilight a crash course in intimacy...with the help of a mutual friend.

(Cover art is property of TheButcherX. Source unlinked due to mature content.)