The term 'testi-mony'

[Shia Islam]

It was the custom in Ancient Rome for the men to place their right hand on their testicles when taking an oath. The modern term 'testimony' is derived from this tradition.

Oath - Wikipedia, the free encyclopedia

 

[enchanted_one1975]

Any tradition that involves a touching of such parts can't be all that bad.

 

[tumbleweed41]

It was also a custom in Semitic tribes to swear "under the thigh"

"And Abraham said unto his eldest servant of his house...Put, I pray thee, thy hand under my thigh: And I will make thee swear by the Lord...."