The Remorhaz (page 258 MM) has an ability called Heated Body:
Heated Body. A creature that touches the remorhaz or hits it with a melee attack while within 5 feet of it takes 10 (3d6) fire damage.
How often does this damage occur, and what exactly is the scope of qualifying scenarios where this would trigger?
If another creature A is grappling the remorhaz, does damage only occur on creature A's turn, only on the remorhaz's turn, once per round, multiple times in a round?
Also, if a creature touches the remorhaz, damage occurs, but what happens if the remorhaz touches the creature? The damage from Heated Body is included in the remorhaz's Bite attack, but not in its Swallow ability. Will the creature swallowed by the remorhaz take 6d6 acid damage + 3d6 fire damage (since the creature is touching the remorhaz inside of it), or only the acid damage?