However , it is common and normal for an erect penis to point nearly vertically upwards , nearly vertically downwards , or even horizontally forward . The angle depends on how long a man 's suspensory ligament is . Although many erect penises point upwards , it is common and normal for the erect penis to point nearly vertically upwards or nearly vertically downwards or even horizontally straight forward , all depending on the tension of the suspensory ligament that holds it in position .