What is Situational syncope?

Tussive (cough) syncope 
It is rare and it is produced  with a paroxysm of nonproductive violent coughing, resulting in persistent increase in intrathoracic pressure, reduction in venous return to heart and hence reduced cardiac output. The victims are almost exclusively middle-aged, overweight men with lung disease.
Micturition syncope
Is diagnosed when syncope occurs during or after urination.
The person has almost always just arisen from a period of prolonged recumbency.
Onset is abrupt with little or no warning; duration is brief and followed by full recovery.
Deglutition syncope
It is uncommon. Certain types of food or carbonated or cold beverages
can stimulate esophageal sensory- receptors that trigger reflex sinus bradycardia or AV block resulting in syncope.
Defecation syncope 
Occurs in older individuals with constipation and the mechanism is due to valsalva like manoeuvre.