A male exemplar. From my experience, reading & conversations. Well before puberty, a human male gets hard thinking about whatever exemplifies the effective man he wants to grow up to be. Davy crockett, the astronauts, the national anthem, his favorite athlete. When a grown man's team makes a touchdown at the super bowl... Glad you've got a brother that you admire & love. It's a good thing, whatever u decide.
Unwanted erections. Good morning first the simple answer is no. Erections can pop up at all kinds of inopportune times when we are in our adolescence. But, if you have feelings for boys that trigger the erection this does not in any way make you a pervert. It takes some time for our sexual identity to develop as adolescents. Some of us need time and experience. But, please find someone safe to discuss this with.