The thunderbolt, indeed a mighty weapon, represents Krsna's power. In Krsnaloka in the spiritual sky there are cows which can be milked at any time, and they give as much milk as one likes. Of course such cows do not exist in this material world, but there is mention of them in Krsnaloka. The Lord keeps many such cows, which are called surabhi. It is stated that the Lord is engaged in herding the surabhi cows. Kandarpa is the sex desire for presenting good sons; therefore Kandarpa is the representative of Krsna. Sometimes sex is engaged in only for sense gratification; such sex does not represent Krsna. But sex for the generation of good children is called Kandarpa and represents Krsna.