Felting is accomplished with a combination of agitation and drastic temperature changes. You can certainly do it by hand, using a spoon or stick to stir the project. I have a friend who does a lot of felting. She uses her washing machine with very hot water, detergent and runs it through a couple of cycles using hot water for the washing and cold for the rinse cycles.

Annie

I boil water on the stove, pour it into my washer, and agitate....I check it every once in a while, and add more boiling water, if necessary to felt it as much as I want.
Sometimes I first put it in the pot, on the stove, with boiling water, and stir...then pour this whole thing into the machine. I also dye things at the same time I'm felting. I had a lot of wool yarn I got for practically nothing, but didn't like the colors, so I use this process to not only felt my 'product', but turn it into a color I like.

I've been felting a lot of small stuff by hand. Just hot water, as hot as I can stand in my kitchen sink, a little dish soap and I rub the heck out of it, mashing it around a lot and rinsing until all the soap is gone. Then put it in icy cold water for a bit, squeeze it out, shape it and let it dry. If it doesn't felt enough for you the first time, you can do it again until you get the desired results.

good luck!
Robin