When both the little fingers interlock each other we get the Kilaka Hasta.
Lets take a look at the Viniyoga shloka (uses)
snehe namranulape cha kilako viniyujyate
The shloka says that this kilaka hasta is used to denote
- A feeling of Love and affection
- Funny talks, hilarious conversation etc
Watch the video and check out the Kilaka Hasta from 0 to 0.20 sec .