Pretty nice, I guess she was the boob submission sender and have a complex about it.
Had the misfortune to read a NTR with a track girl similar to her, tan, shrot hair, active, but with big booba, she unfortuantely run worse and was corrupted when down with her morale, runners don't need booba (said from a booba lover).
That 5th volume cover is bait...I bet is just one of MC fantasies, or at the very most the girl was asked to be the deomn for some event and was given a lewd costume.