Benefits for donating towards this seva are as follows:
Jhulana-yatra is a festival to celebrate Radha Krishna’s pastime of swinging on a golden swing everyday until Balarama-purnima.
Krishna is decorated nicely and seated on a swing . All devotees wait patiently in a queue to swing Their Lordships. The swing (jhulana) beautified with splendid flower decorations, colorful beads, etc. A special flower rope is used to pull the swing. An arotik is performed after Sri Sri Radha Madhava are seated on the swing, and devotees bring a variety of bhoga to please Their Lordships. Kirtana and bhajans go on for almost two hours, and many visitors join in to pull Their Lordship’s swing.
In this regard Sri Hari-bhakti-vilasa states,
To please Sri Hari, devotees hold numerous festivals on every occasion and continuously perform sankirtana. According to their ability, the devotees serve the Lord during the summer by placing Him on the boat, taking Him out on a procession, applying sandalwood on His body, fanning Him with chamara, decorating Him with jeweled necklaces, offering Him palatable foodstuffs, and bringing Him out to swing Him in the pleasant moonlight.