third wheel
When two people act ”intimate” close to someone clearly trying to focus on something else (such as sleeping, studying, reading, etc.), usually (but not necessarily) prompting the person trying to focus to feel embarrassment, unamused, or arousal.
Intimate activities may be romantic (Ex: flirting) or sexual in nature.
If the intimate activities are sexual, then the sexual activities should not be happening to the person when he/she is trying to focus nor should they be happening in public. For this pool such activities should be done in the safety of the performers' own private space.
The person trying to focus should not be intentionally focusing on witnessing/listening to the intimate acts such as in voyeurism or eavesdropping.