G-BOM couple is known for GD's love for teasing/imitating of Park Bom.
G-Dragon posted a message on hi UFO Town (not sure when exactly maybe around 2008-2009)
where he expressed his feelings towards Big Bang's maknae, Seungri:

G-Dragon: Seungri is a friend who has a burning passion even bigger than a flame. There are many fans or people in general who watch us on TV and misunderstood us because I tease Seungri so much that they think that Seungri and I don’t have a good relationship. But this is really not the case, I care a lot for Seungri. Maybe its because I’m a guy that its become my habit to always tease him in order to express my affections towards him instead of hugging him. Because of this though we made a lot of people upset but… I really don’t mean it like that. I’m thankful to Seungri for liking me so much despite the fact that I annoy him so much. Seungri has now grown up, he is 20 years old so from now on I’ll be more respectful to Seungri in the future everyone
Translated by: alee@ibigbang

Could it be that the same thing applies to Park Bom.. but in a romantic way?
Come on, it's one of the signs of when a guy likes a girl!

Watch this video of how G-Dragon likes teasing Park Bom