Vagina oozing cheese during sex

[BoboBrowne]

What the hell is the cheesy, chalky, buttery looking substance that sometimes comes out of a girls vagina during intercourse?

Here's a clip of Ron Jeremy fucking Premium Link Upgrade to show you what I'm talking about. Her pussy is leaking margarine around the 7:20 mark.

edit: sorry link wouldn't work. But google Premium Link Upgrade + Ron Jeremy + outdoor sex.