Plus-Sized Elf: Second Helping! Vol. 3 by Synecdoche

TIME TO TIP THE SCALE!Massage therapist Naoe Tomoatsu is always coming up with new ways to get his otherworldly clients back into shape. He faces a new challenge, however, when the already-buff Stheno, a Gorgon, comes to him for advice on gaining weight! Then later, Kuroeda is forced to employ a mysterious visitor at the convenience store who ends up becoming a serious pain in her (ample) behind.
Binding: Paperback / softback