Speaking of fathers and sons...
That's the unfortunate answer for the vast majority of young men entering puberty. If we don't have someone to teach us about it, we all manage to stumble upon masturbation at some point. But, there is so much more to it than we imagine when we become aware of our cocks.
I was lucky - after I discovered him jacking off one night, my older brother and his buddies lead me along. There was no sense of shame or embarrassment between us.
Being discovered stroking away shouldn't be cause to believe we've been "caught" jacking off.
Finding a guy stroking away, enjoying himself shouldn't be cause for ridicule.
Have you ever been discovered masturbating?
Did it embarrass you?