dvau māsau tatra cāvātsīn
madhuḿ mādhavaḿ eva ca
rāmaḥ kṣapāsu bhagavān
gopīnāḿ ratim āvahan
dvau -- two; masau -- months; tatra -- there (in Gokula); ca -- and; avatsit -- resided; madhum -- Madhu (the first month of the Vedic calendar, at the time of the spring equinox); madhavam -- Madhava (the second month); eva -- indeed; ca -- also; ramah -- Balarama; kshapasu -- during the nights; bhagavan -- the Supreme Lord; gopinam -- to the gopis; ratim -- conjugal pleasure; avahan -- bringing.
Srila Sridhara Svami states that the gopis who enjoyed conjugal affairs with Sri Balarama during His visit to Gokula had not taken part in Sri Krishna's rasa dance, being too young at the time. Srila Jiva Gosvami confirms this statement by quoting a phrase from the Bhagavatam (10.15.8) -- gopyo 'ntarena bhujayoh -- which indicates that there are particular gopis who act as Lord Balarama's girlfriends. Furthermore, Jiva Gosvami states that during the Holi festivities celebrated when Krishna killed Sankhacuda, the gopis Lord Balarama enjoyed with were different from the ones Lord Krishna enjoyed with. Srila Visvanatha Cakravarti agrees with this explanation.