Sentence:  This reasoning was used only months later in a decision that further extended common law concepts by holding <WSD>mutual masturbation</WSD> between two males criminal. The judge reasoned that "there can be no distinction between the case where sexual gratification is obtained by friction between the legs of another person, and the case where it is obtained by friction against another's hand." 
Meaning of the word marked with <WSD> tags:  A sexual activity in which two or more persons simultaneously masturbate one another.