Serious answers only: Rumbling Penis?!
Question: Serious answers only: Rumbling Penis?
Answers:
You could be going through a growth spurt which could cause muscle spasms. The spasms could make sounds that sound like rumbling. Another possibility is you have some loose air trapped in your urethra and that could be coming out. As long as you don't have any pain and it doesn't last over a day I wouldn't worry about it. It it continues I'd recommend a check up.
Perhaps you swallowed a vibrator, which causes erections when it vibrates against a certain are of yer stomach?
Yuh
Chop it off, then it'll go away
Personal experience
I bought a rumbling penis for my girls bumhole and it was like 20 bucks. Your lucky man that thing saves you a whole 20.