When I googled "kosohitavatthaguyha" I found this

According to the Tipiṭaka, one of the 32 Signs of a Great Man is that ‘the cloth-hidden is encased in a sheath’ (kosohitavatthaguyha, M.II,135). This was interpreted to mean that the Buddha’s penis could be drawn into the body and remain there as with some animals like horses, cattle and elephants.

the banyan tree was considered sacred, and the Buddha is supposed to have had the proportions of a banyan tree (nigrodhaparimaṇḍala), i.e. the length of his outstretched arms equalled his height. He is supposed to have had long curved eye lashes (gopakhuma) and a very long tongue (pahūtajivhā), both of which are features of the cow, an animal the Indians greatly revered.

According to the Ṛg Veda, an attractive penis would be big and thick like a club. The Atharva Veda has a prayer to make the penis long and hard like a taut bow and also contains spells to make it as long as that of the wild ass, the elephant or the stallion. The Rāmāyana on the other hand, describes the auspicious man as having a slender, short penis with a smooth glans and drooping testicles. The Buddha seems to have had an aesthetic appreciation for this part of the male anatomy too.

It seems probable that like the ancient Greeks, the Buddha’s contemporaries considered having a penis whose foreskin (kosa) remained over the glans (makula) when either flaccid or erect, to be a sign of beauty and nobility and that at a later period this physical characteristic was attributed to the Buddha.

I didn't know Buddhism had so much dick lore ~ I want that horse cock spell.