Edit...We have the stretching kits. Still a no go. His penis is never going inside...he just has a fetish to get his semen inside but penetration isn't necessary and I would rather not use a funnel.

Update: to the person who suggested the plug. Worked like a charm and added a new favorite toy. Had never seen them before but it was a lot of fun plus he got what he wanted. Thanks so much and hope others try them out.