A funnel body comprising a base plate, pull rod, and an outer wall. The outer wall may comprise a plurality of overlapping leaves or a membrane joined to a frame, with the outer wall movable between a collapsed position and an extended position and optionally biased towards the extended position. The funnel body may be moved into an extended position for use as a funnel and moved into a collapsed position and further retracted into a receptacle for storage within the receptacle when not in use. Also provided is a funnel assembly, comprising the funnel body and a housing, wherein the base plate of the funnel body is housed within the housing and positioned between upper and lower stops that engage the base plate and thereby prevent the base plate from exiting the housing. Further provided is a receptacle in combination with the funnel assembly and a method for modifying a receptacle to include a funnel assembly.