The pump has a pump body with an opening (24) to communicate a pumping chamber with an interior of a receptacle. A lip (40) is fixed on the body to prevent communication between the chamber and receptacle, after the displacement of mobile assembly in a product distribution direction from a rest position. Another lip (41) is placed above the former lip to prevent the communication across an interior of the body and the opening. An independent claim is also included for a receptacle equipped with a pump.