Thanks for your question.
Since when is this happening? Did you have any investigations done? Do you take any daily medications? Please describe your present symptoms in more detail.
Thanks for your reply.
Basically this needs to be informed to your doctor. This is because before treating this symptom with medications your doctor needs to do certain investigations such as hormonal studies to know the reason for your increased libido and prolonged erection. If there is any underlying cause then treating it will reduce the frequency of the erections. Also a prolonged erection may lead to complications such as erectile dysfunction, hence this can be an emergency and therefore I would advice you not to delay consulting your doctor about this any further.