What is Grilling?
1.
To continuously stare at someone, giving an impression of disliking.
That girl is grilling at us, let's grill her back.
2.
the act of looking at an object very intensly
Bob was grilling the cheese puff.
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3.
The act of kicking someone up the arse from behind whilst they are bent over (for example while tending the grill) and catching the genital area with the tip of ones shoe/boot.
Bob had severely pissed off Penelope the night before by surprising her with a hot Karl, so in the morning when he bent over to pick up his underpants she decided to administer a grilling that would knock his knackers into next week.
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4.
To be going down on a girl either vaginally or anally
Man i was so drunk that i grilled that girls ass