Godan verb with 'ku' endingtransitive verb word usually written using kana alone only applies to しごく to draw through one's hand;to stroke (e.g. a beard)

Godan verb with 'ku' endingtransitive verb word usually written using kana alone only applies to しごく to work someone hard

Godan verb with 'ku' endingintransitive verb word usually written using kana alone to masturbate

Godan verb with 'ku' endingtransitive verb to thresh;to strip