Then what about my erected penis size 3.8 inches is it able to satisfy my girlfriend.

Question

A study found that the average penis size for an erect penis is 14.2 cm (5.6 inches) Average circumference of an erect penis is 12.2 cm (4.8 inches). If your penis size is 14.2 cm at erect time then you is perfectly ok. 
Excessive masturbation during teenage time is also a reason for micro penis. If your penis length is small for masturbation habit of your early life it may be overcome by taking proper homeopathic remedies.
Homoeopathic constitutional treatment will give you a permanent cure without any side effects and minimum dose itself.
You can easily take an online consultation for further treatment guidance

Himani Negi · Accepted Answer

A study found that the average penis size for an erect penis is 14.2 cm (5.6 inches) Average circumference of an erect penis is 12.2 cm (4.8 inches). If your penis size is 14.2 cm at erect time then you is perfectly ok. 
Excessive masturbation during teenage time is also a reason for micro penis. If your penis length is small for masturbation habit of your early life it may be overcome by taking proper homeopathic remedies.
Homoeopathic constitutional treatment will give you a permanent cure without any side effects and minimum dose itself.
You can easily take an online consultation for further treatment guidance

Mahesh Nawal · Answer

3.8 inches erect penis is sufficient for pleasurable penetration in the vagina. Because most sensory part of the vagina is it's first two inches. She gets pain or pleasure, it's only up to outer two inches of the vagina. Satisfaction or climax or Orgasm has no relation with penetration?.