SB 10.18.15

kvacic ca dardura-plāvair
 vividhair upahāsakaiḥ
kadācit syandolikayā
 karhicin nṛpa-ceṣṭayā
Word for word: 
kvacit — sometimes; ca — and; dardura — like frogs; plāvaiḥ — with jumping; vividhaiḥ — various; upahāsakaiḥ — with jokes; kadācit — sometimes; syandolikayā — with riding in swings; karhicit — and sometimes; nṛpa-ceṣṭayā — with pretending to be kings.
Translation: 
They would sometimes jump around like frogs, sometimes play various jokes, sometimes ride in swings and sometimes imitate monarchs.
Purport: 

Śrīla Viśvanātha Cakravartī Ṭhākura explains the word nṛpa-ceṣṭayā as follows: In Vṛndāvana there was a particular place on the riverbank where people who wanted to cross the Yamunā would pay a small tax. At times the cowherd boys would assemble in this area and prevent the young girls of Vṛndāvana from crossing the river, insisting that they had to pay a customs duty first. Such activities were full of joking and laughter.