Shlokam:

Like the rising sun (bright), with four hands, necklace and bracelet, in sacred robes, hair wound as crown, with three shining eyes, pArvatito the left, Fragrant, with kumAra in the middle, to that greatsOmaskanda, with deer, protection, boon giving postures and axe, salutations.

Purana of the deity :

saha umA skandar : with umA and skandar (bhOga mUrti)

mahA viShNu wanted to have a son who would be an example of charm. For that he worshipped the God. Delighted with the worship of the great viShNu, Lord shiva appeared to provide the boon he looked for. At that time mahAviShNu showed no respect to goddess shakti. Irked by that shakti cursed that the charming son viShNu would get would be burnt away by the Lord. (1) viShNu was shocked to hear this. Now he worshipped again the Lord along with goddess shakti as well as their child Lord skandha. Pleased by the worship shakti blessed that the son of viShNu who would get burnt away by the God, would again be brought back to lify by the Grace of God. By this boon mahAviShNu got the charming lord of lust – manmata . The form worshipped by mahAviShNu is the saha umA skandha mUrthi or sOmAskandha murti.

mahA vishNuworshipped this mUrti for long time having at his heart. Later brahmA requested mahAviShNu for this mUrti and got the same. He worshipped the mUrti and then indra got the same as boon. The chOza king muchukunda obtained it from indra, installed in the seven vidaN^ga(2) places.

Courtesy: www.shaivam.org