Found in Gadadhar Pran's commentary to GLA, Introduction to Madhyahna lila.
zrI-rUpa-darzita-dizA likhitASTakAlyA
zrI-rAdhikeza-keli-tatir mayeyam
sevAsya yogya-vapuSAnizam atra cAsyA
rAgAdhva-sAdhaka-janair manasA vidheyA
I have followed the direction of Sri Rupa Goswami�s Smara�a-mangala to elaborate on Radha Krishna�s ashtakala lilas. Raganuga sadhakas should perform manasi seva of these pastimes while mentally conceiving their siddha deha fit for serving in the lila. (Gla. 23-94)
Srila Vishwanath Chakravarti�s granddisciple, Sri Vrindavan Chakravarti, in his commentary on this verse, glosses the words yogya-vapuSA as, �in the suitable siddha-deha fit for serving within the lila, received through the guru�s instruction� (zrI-gurv-AjJA tat-sevA-yogya-siddha-vapuSA).