Regarding the size, an erect penis of around 4 inches may be enough for some people, but it varies. Premature ejaculation can happen for various reasons. It's best to consult a healthcare professional for personalized advice on both concerns. Communication about preferences and needs with your partner is also important for a healthy sexual relationship.

Masturbation is normal and healthy sexual activity for most people and normally does not cause permanent damage to the penis. But excessive or aggressive masturbation may lead to temporary discomfort, such as soreness. Its impt to practice moderation and use lubrication if needed to avoid excessive friction.

The possibility of your boyfriend's methamphe­tamine consumption leading to a failed urine­ drug test for you tomorrow is improbable. The like­lihood of drugs entering your system through his e­jaculation during intercourse is minuscule. 

If you're experiencing pain, redness, or swelling in your penis, it's important to see a doctor for evaluation and treatment. While waiting for the appointment, keep the area clean, avoid further irritation, and don't try to pop any bumps. Consider any recent changes in products you've used.

The lack of movement in CT scan may not always be associated with kidney failure. Talk to a urologist they can recommend suitable treatment plan for you

Considering your symptoms, it is best to see a urologist. The symptoms of a urinary tract or prostate problem include regular voiding, pain on the side, and tip discomfort. Treatment must be sought to ensure proper diagnosis and treatment.