SB 10.67.13

tā helayām āsa kapir
 bhrū-kṣepair sammukhādibhiḥ
darśayan sva-gudaṁ tāsāṁ
 rāmasya ca nirīkṣitaḥ
Synonyms: 
tāḥ — them (the girls); helayām āsa — ridiculed; kapiḥ — the ape; bhrū — of his eyebrows; kṣepaiḥ — with odd gestures; sammukha — by standing right in front of them; ādibhiḥ — and so on; darśayan — showing; sva — his; gudam — anus; tāsām — to them; rāmasya — as Lord Balarāma; ca — and; nirīkṣitaḥ — was watching.
Translation: 
Even as Lord Balarāma looked on, Dvivida insulted the girls by making odd gestures with his eyebrows, coming right in front of them, and showing them his anus.
Purport: 

Śrīla Prabhupāda writes: “The gorilla was so rude that even in the presence of Balarāma he began to show the lower part of his body to the women, and sometimes he would come forward to show his teeth while moving his eyebrows.” Śrīla Viśvanātha Cakravartī states that Dvivida would come right up to the women and move about, urinate and so on.