The patient should be positioned for comfort, ., in Sims position (lying on the left side with knees and hips comfortably flexed). A chaperone and/or a drape should be provided for patient safety, comfort, and dignity. After an explanation of the procedure to the patient, several mL of surgical lubricant are placed on the examiner's glove, usually on the index finger. The examiner visually inspects the anus and perineum, then places the gloved finger on the anal opening while asking the patient to bear down gently. After the finger enters the anus, it is used to sweep circumferentially around the interior of the distal intestine. It is then directed anteriorly (when examining a male patient) to evaluate the consistency, size, and nodularity of the prostate gland. Samples of stool obtained during the exam may be sent to the lab to test them for the presence of occult blood.
In behavioural tests of anxiety , a low dose of N
2 O is an effective anxiolytic , and this anti-anxiety effect is associated with enhanced activity of GABA A receptors, as it is partially reversed by benzodiazepine receptor antagonists . Mirroring this, animals that have developed tolerance to the anxiolytic effects of benzodiazepines are partially tolerant to N
2 O .  Indeed, in humans given 30% N
2 O , benzodiazepine receptor antagonists reduced the subjective reports of feeling "high", but did not alter psychomotor performance, in human clinical studies.