Is it normal to get random boners at the worst possible time?

Yes this a problem if called up to the front of the class, obviously it shows through and awkward, actually considering how other kids are these days, I take it by your question your young and in what grade 5 or 6, well depending on your actual age, I would advise differently.

So say your at the age when I experienced the same problem, 5th grade, I was popular with the girls and upon the one awkward time to be called up to the front of the class, in those days Levi 501 button fly jeans were really different, you had to wash then even to ware them, well I liked tighter fitting jeans so while sitting at these chair desk combo flip top , if any unexpected boners were easily concealed, but it happed at almost the precise moment of discovering this independent problem occurring out of nowhere right when the teacher asks me to the front of the class, I responded to her, you want me, me to come to the front of the class? How come me, I honestly still can picture it like happening now, my luck the pure fright of all these girls seeing the big B helped a bit, and with the stalling tactics, I didn’t feel pressure like before.

I could only hope it looked as I thought it felt? The reality of it was still a noticeable lump that got noticed, Nobody said a thing in class, afterwards I got the scoop, girls actually thought I did on purpose, like what purpose could that be in class while attending 5th grade?

We did have curiosity of our anatomy and that of others male or female too at that age and even earlier then the fifth grade, is a natural process of growing up and part of life’s education. The best way to help you with you next unexpected boner, have your shirt out and not tucked your pants, a longer tee shirt works and seems a fashionable ok thing to wear, it can help conceal it somewhat.

But you also could just ignore it, stand up proud to be a man, a young man!
Anybody says one word, you could easily have the killer come back, which would have the attention on the big mouth and class laughing. Be happy its natural and you will find out more and more about yourself and others and life in general. Don’t rush to grow up; life for a kid should be simple without complications. Here is some food for thought?

The funny thing is when guys get older; not old like your grandfather, just a few years or so, especially ones who feel they are inadequate in size find substations and pretend they got this monster lurking in his pants while attending parties or social gatherings that is one mistake you should never make, it stays with you for quite a while be yourself and remember most of those who have nothing good to say or make fun of other are hiding the very thing their making fun of or humiliating.

Dude, begin to worry when you stop getting random boners, or can't get it up at all. This may or may not happen as you age, so for now appreciate the wood.

That is the nature of the random boner.