My first cum was the way Submissivemartyn say it
So I think that counts. Was amazing

I got my hands on a piece of profiled foam rubber from the inside of a speaker box.
I rolled it up, fixed it with a few rubber bands and put a thin plastic bag in it.
With a bit of vegetable oil as lube, it was almost as good as some commercial products
I've tried later in life.

Don't know whether this counts but here goes.I once put my cock on the toilet then put the toilet seat on top of my cock.Then I pushed down on the seat and fucked away merrily till I came.