Garry's Mod Wiki

Entity:Use

You might be looking for the "ENTITY:Use" hook, which has the same name as this method.
  Entity:Use( Entity activator, Entity caller = NULL, number useType = USE_ON, number value = 0 )

Description

Simulates a +use action on an entity.

Arguments

1 Entity activator
The entity that caused this input. This will usually be the player who pressed their use key
2 Entity caller = NULL
The entity responsible for the input. This will typically be the same as activator unless some other entity is acting as a proxy
3 number useType = USE_ON
Use type, see USE enum.
4 number value = 0
Any value.