ii. Procedure and Design: On each day of the study, therapy will begin with the Baseline phase (Condition A) and record the psychological (visual analogue scales of Anxiety, Disgust, Belief in obsession, Strength of urge for compulsion, Strength of belief in Theory A/B, Feeling of being supported, Readiness to face the fear) and physiological measures (HR recording) on 3-5 consecutive 5min intervals or until stable baseline measures are achieved. After that, the participant will proceed with the Intervention phase by applying ERP with the use of triggers as identified on their individual hierarchy. Each ERP session will follow the same structure by first obtaining the session baseline at 3 time points, then exposure to trigger and continue with preventing the response while applying the cold face mask for 5 minutes (Condition B) or without using the face mask (Condition C). Psychological and physiological measures will be obtained in 5 minute intervals until return to session baseline. ERP sessions will follow in alternating order for 4 sessions per day (Day 1: ABCBC, Day 2: ACBCB, Day 3: ABCBC). All baseline and exposure measures will be recorded by the investigator who will by accompanying the participant during the procedure. Cold face gel masks will be stored in refrigerator at the ADRU and will be available to the participant as required.