PG Diploma in Sexology and Psychosexual Counseling. For More Info WhatsApp- 9604715783/9359863878. Excitement: Men: Erection of penis, marked increase in its size, and a rise in its angle. Erection may be triggered by penis itself or by sexually stimulating sight, smell or thought. It occurs in 3to 8 second. A small penis may double in length, while in a large penis lengthening is less marked. Partial elevation and increase in the size of testes.