"think of it" is a phrase you use when you see someone eat a booger from their nose. (or a pimple, ugh)
then you tell your friend and say "think of it" so that person will know what you mean and will feel ill.
for example
Person nr 1: Hey Simon
Person nr 2: yes?
Person nr 1: hehehe think of it
Person nr 2: AAAAAHHHHHHHHHHHHHHHH (feeling ill and scared)
The most beautiful, sweet and funny person you'll ever meet. Even when you're feeling down, they will always make you happy. Their smile and the little glimpt in their eye when they squint when they smile is just... perfect!
Guy 1: You talking to any girl lately?
Guy 2: Yeah, started talking to this girl Eela
Guy 1: NO FUCKING WAY DUDE, Im f#cking jealous. Hold onto her, Eela is the best out there!