"Kalong" is a root word. It is also at times used as a verb by itself. You will hear this usually said inside a crowded vehicle when children a made to sit on someone's lap and thereby provide some more seating spaces for bigger people.
Jeepney driver: "Paki-kalong na lang ang bata kung hindi ninyo ibabayad" = Please just have the child sit on your lap if you will not pay his fare.
"Masikíp na tayo dito sa kotse kaya kumalong ka na lang sa ate mo" = We're already crowded here in the car so just sit on your elder sister's lap.
"Huwag ka nang nagpapakalong sa nanay mo kasi malaki ka na" = Don't ask your mother to sit you on her lap anymore since you're already big.
The Tagalog word for "lap" is "kandungan", with "kandóng" as its root word. We sometimes use "kandóng" in place of "kalong".