Krsna performs rasa lila of two varieties, one in the autumn season and one in the spring season, on vaisakha purnima. Balarama also performs rasa dance at this time.
In order to keep the gopis in Vrndavana satisfied, Lord Balarama stayed there continually for two months, namely the months of Caitra and Vaisakha. For those two months he kept himself among the gopis and he passed every night with them in the forest of Vrndavana in order to satisfy their desire for conjugal love. Thus Balarama also enjoyed the rasa dance with the gopis during those two months.
Krsna Book II p.78