Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
Everyone always seems to yell at you when you start to toy with your towel and your towel moves (たわむ). Just because you don't have anything on under it doesn't mean you can't play with it! Right?!
I took a picture of the puppy and the girl playing with it.