Clitoral erection is the result of a complex interaction of psychological, neural, vascular, and endocrine factors, and is usually, though not exclusively, associated with sexual arousal.
[3] This swelling and shrinking to a relaxed state seems linked to nitric oxide's effects on tissues in the clitoris, similar to its role in penile erection.
Clitoral erection occurs when the corpora cavernosa, two expandable erectile structures, become engorged with blood.
[9] Erick Janssen (2007) elaborates on this reporting that "the corpora cavernosa of the clitoris are essentially similar to that of the penis except that there is no subalbugineal layer interposed between the tunica albuginea and the erectile tissue.
In the penis, this[10] tissue engorges with blood during sexual arousal and becomes compressed against the unyielding tunica, creating penile rigidity – a true erection.
[11] Among capuchin monkeys, clitoral erection is possible and makes the clitoris more visible than in its relaxed state where it is hidden by a preputial fold.