On god

Typically used for expressing the seriousness and/or truthfulness of a statement or action.

“On god I won’t hit you. ON GOD I won’t hit you.”

“He really said that?” “On god.”

Unga Bunga grip

Holding a utensil (for eating or writing), or any other long object (flashlight for example) tightly clenched in your fist.

He held his fork and knife with that Unga Bunga grip.