Draining Kiss

You drain the life from those you kiss. You kiss a willing creature or a creature grappled by you. The target must make a Constitution saving throw, on a failed save the target takes 1d10 + your spellcasting ability modifier Psychic damage. You gain a number of temporary hit points equal to half of the damage dealt rounded down. The target's hit point maximum is reduced by the amount of Psychic damage taken. The target dies if this effect reduces its hit point maximum to 0.

The damage of draining kiss increases by 1d10 when you reach 5th (2d10), 11th (3d10), 17th (4d10)