Sentence:  `` You 're boiling milk , ai n't you '' ? soothing it with his hand , knowing the whiskered jowls and the swollen smoothness of teats that <WSD>wrinkled</WSD> expectantly to his touch . 
Meaning of the word marked with <WSD> tags:  make wrinkles or creases on a smooth surface; make a pressed, folded or wrinkled line in