rough and tumble play See play, rough and tumble. rub dorsum Lean against vertical tree trunk and rub wet shoulders or back against it, often holding arms upward, after heavy rain. May lie supine on rock, ground, grass, horizontal bough, or day-bed to rub against surface. Recorded at Gombe. Also in bonobos of Wamba. 5. See video. rub dorsum to conspecific Juvenile may lean against back of adult male to solicit play. Rare at Mahale. Idiosyncratic?. See video. rub genitals 159 rub genitals Female rubs genitals against another female. At Mahale rarely seen, and limited to pairs in which one participant is juvenile or adolescent. At Bossou more frequent and ventro-dorsal, and put rump to position seen. Bonobo females often show species-specific G-G -rubbing as reassurance. See video.