I think this falls into the category of "unneccessary frills".

The point of the funnel (I thought) was the same as that of a gag that keeps an unwilling woman's mouth open so that she can't resist having noxious(?) fluids dripped in. This woman is obviously cooperating. The only effect this funnel would have is to reduce the amount of cum that made it to her mouth (the rest sticking to the walls of the funnel).

Of course, that may have been her plan!

By the way Red, she's about the shape I'm looking for. Do you have her phone number?