It's a natural setup for comedy. And erotic situations. Struggling to deal with colossal breasts, a colossal cock, perhaps hypersexual urges or hair-trigger floods of ejaculation/breastmilk... It instantly makes a story with tension and meaning out of "And then something sexual happened again". It can create empathy or envy. It can create tragedy and comedy. It can create accidental or intentional sexual moments.