facesitting

Use rating:s when:

• The context is strictly comedic, accidental, or situational.
• There is no erotic focus or fetishistic.

Example:

Use rating:q when:

• The context is fetishistic or erotic, even if not graphic.
• There is no sex acts occurring (oral sex, anal sex, rimming, etc.)
• Post does not contain in general anything that falls under the explicit rating (see e621:Ratings).

Example:

Use rating:e when:

• Post depicts explicit activities such as oral sex, masturbation and penetration.
• Post depicts genital fluids, feces or urine.
• It's clear that explicit activities are occurring, even if it's obscured from direct view (for example by big butt).
• Genitals or anus are visible.

Example: