Hydra tortures someone by making the Asset swallow them and letting them be slowly, painfully digested alive in him. Them they are reformed and either tortured this way again or made to think it didn't happen.
The Soldier does not enjoy it, he hates the stretch of his stomach and the ways his prey thrashes and screams and the knowledge that he's doing that to a person and can't stop it. Bonus if Brock fucks Winter while groping that huge shapeless gut.