Sex face — it's the face we make when we're having sex.

Also known as the O face — you can guess what that stands for — it is a primal and universally appreciated erotic expression.

"It's good to be the king," Sexpert Chantelle Austin told Cosmopolitan, when explaining why it was such a turn on. "Everybody wants to know they are doing it right. It's part of our nature to want to be the best."

Sometimes the O face is a genuine expression of pleasure. Other times it is a put-on for a partner who just isn't working.

In any case, below are nine O Face GIFs for almost every situation.

Oh shit — are those teeth?:

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When you're spending the weekend at his parents' place:

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After a bad day at work:

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When the 'rents be out:

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This isn't working:

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Out in the open and just don't care:

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When the best man is just irresistible:

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When it's been a while:

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Sebastian!?:

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