In the video, the dominant girl uses frosting to write the word "slut" on the other girl's chest...

I've noticed that an increasing number of real girls (not pornstars) seem to enjoy having this done to them, though usually with lipstick and will actually ASK you to do it after signing their name or something similar near the mans privates with the same tube of lipstick...

Does the "technique" of writing something on a girl (usually something like 'slut', 'whore', or 'hot mess'), either with whipped cream or lipstick, have a name???

I dunno. If there isn't already, I am gonna coin "slutograph".

Excellent. This should not cause any confusion whatsoever vis-a-vis men's perception of women.