I actually got my first boner when I was four and learning how to swim at a public indoor pool. The foid teaching me how to swim would put me on her back and had me hold on to her while she swam and I guess my pp being against her butt cheeks made me get hard. When she stopped, she started giggling and I didn't know why. The boner would not go away. When I had the safety floats taken off of my arms, she would hold on to my lower torso while I was swimming to keep me above the water. Her hands just gave me a boner because they were close to my peen but I was four and I thought something was wrong with me. I got really scared and started crying because of my boner but she thought it was because of me being afraid of drowning. When she lifted me out of the water... everyone there saw my boner sticking up in my swim trucks and THE ENTIRE INDOOR POOL AREA ERUPTED WITH LAUGHTER. The swim instructor lady couldn't stop laughing and covering her mouth. My mom was laughing but my dad got super pissed off and was embarrassed.
My dad was so upset that he told me to tuck my boner into my waistband and then he grabbed my by the arm and said "THAT'S ENOUGH SWIMMING TODAY! WE'RE GOING HOME NOW!". I was still scared that I was going to die from my boner and kept asking my parents what was wrong on the car ride home but they never told me. From that point on, I knew that boners were something you didn't want other people to know you had.