A medical valve may comprise a valve stem and an operation portion. The operation portion may include a stationary portion, a movable portion which is movable relative to the stationary portion and fixed relative to the valve stem, a seal disposed between the stationary portion and the movable portion, and a biasing member. Movement of the movable portion in a first direction may cause deformation of the biasing member, such that a restorative force of the biasing member urges movement of the movable portion in a second direction opposite the first direction. A frictional force between the seal and one of the stationary portion and the movable portion resists the movement of the movable portion in the second direction.