Omega Sherlock doesn't have check ups where doctors need to check his reproductive organs/system. He finds it upsetting when they prod and poke him where it's highly sensitive. He doesn't like it when they manipulate him.

His alpha, john, gently coaxes Sherlock and talks him into relaxing while John does the medical, which leads to more sex once Sherlock isn't scared anymore. But he's still tense, after the clinical methods and john talks Sherlock into relaxing as he pushes his cock into his tight mate, eventually knotting him.