I think that the "forced move" could be extended to something more easy on your opponent: why not suggest a series of moves to it. So, you can start the game with 1.e4 and suggest to the opponent the line
"1...e5 2.Nf3 Nc6 3.Bc4 Bc5" and, if your opponent accept it, all these moves are registered as being played, and the game goes on move 4, or, if your line goes "1...e5 2.Nf3 Nc6 3.Bc4", then black answers with their own move, that can be 3...Bc4, or another one. It can be extended to the point where you suggest more than one line of play to your opponent. I think it is somewhat related to the "if" moves in Correspondence/Postal Chess (http://www.correspondencechess.com/apct/rules.htm).
In the case of a forced mate, you can do as I did someday: I pointed that there was a forced mate solution to a game (I listed all moves), and then my opponent accepted it immediately, resigning the game (unfortunately, it happened only one time).
There are a lot of people who take pleasure in chalking up moves and being what is known as the "MAP" (Most Active Player) so often people prolong matches or choose not to resign them just to make the moves. Each to their own, I guess, you just have to sit it out until you get the mate.