Is it normal for your erect penis to point down?
If your erect penis is straight or nearly straight but hangs downward when erect, then, yes, it is perfectly normal for some men. There is a ligament near the base of the penis that controls the angle of the erect penis. For some men, especially when they are young, the erect penis will point almost straight up. For others it will point out and upwards. Still others will see their erect penis point straight out or even downwards.
However, if only the end of your erect penis points downwards, then it is an indication of a problem. Small bends are not a problem, we are talking about significant bends here. One cause is Peyronie's Disease, which is caused by damage to the chambers which swell to cause an erection. You have three in your penis, two on top and one on the bottom. If the one of the bottom has been damaged, it will cause the erect penis to hook downwards. (In other words, the shaft of the penis bends downward.) This can make sex difficult or even painful. Peyronie's Disease often clears on its own after three or four months. If it does not clear, you will need to see an urologist (a doctor specializing in the urinary and sexual organs) to get treatment.
Another rare but possible problem is a circumcision that removed too much of the foreskin. The tight skin causes the penis to bend in awkward shapes when erect. Sometimes the erection or having sexual intercourse causes the skin to tear. If you experience pain with an erection, it would be very wise to see your doctor about the problem.
A similar problem can occur in an uncircumcised male. Due to a genetic problem, the skin on the underside of the penis is too tight or not fully formed. Thus, during an erection the tight skin causes the end of the penis to bend downwards. Doctors call this condition "chordee." When this is a problem, a man may experience pain during a strong erection. Since the body trains itself, often what happens is that your body avoids full erections to avoid the pain. Hence, many boys don't realize they have a problem until they get married and try to have sex the first time. Basically, if you find having an erection to be painful, you should consult your doctor.
If showing your doctor your problem is too embarrassing to contemplate, consider taking a few digital pictures of your problem in privacy from several angles and then take the pictures with you to show the doctor. This would be better than not going at all.