1. Guys get erections because they get sexually aroused but a lot of the time a guys body can get sexually aroused without the guy really being aroused. Eg a guy can get an erection just from a girl holding their hand on sitting on their lap or even smiling.
2. The second way guys can get erections is because the body has to circulate more blood around the penis every so often for cell regeneration etc. Sometimes people call them "random boners". You get a lot of these during puberty especially when you've just "dropped your balls" (Penis triples or more in size in what seems like a day but is probably a year or so).
There are several ways guys can hide erection. This video shows various ways that are all the tried and tested ways with a funny slant.
Guys get them all the time because they're not always because they're horny. And absolutely any sexual thoughts (which we have lots of) can set it off.
You'll know if someone has an erection because you'll feel a big hard lump of flesh in an area where you were sure there were no limbs.
You know he has an erection if you could see it in his pants or if he's sitting down and really doesn't want to stand up or he's pulling his shirt down. Basically, if he's paying too much attention to his movements and his appearance, it usually means he has an erection. If the guy doesn't have loose clothing or a jacket, it's hard to hide. A good way to put his hand in his pocket, it stretches the pants out so the erection's harder to see.
I'd say that guys get erections at least once a day, I know I do. Usually they're caused by getting turned on. It could be from seeing or even thinking about a hot girl. But sometimes they just happen randomly.
The sight or sound of a pretty girl can make an erection happen in a guy. But if he is trying to hide it, there is no way that you will know. The last thing he wants is for the people in his class to see him with one.
The only real way you could know is if you tried to touch him there.
Most of the time you see a guy slouched over more than usual or he has his elbows on his knees (esp. If they are a teenager) they most likely are hiding a boner as when you are bent over enough your dick will end up between your legs instead of sticking straight up
there are many ways to hide it in very little bikini. Boys can gaff penises in thongs or in women bikini or panties where penises are keepet press. its very great to feel in that way. I can look like a girl when i where bikini even if I am a big penis
well I don't know but when I wear my TYR tight swimshorts an if I get out of the water an it hard to hide if I get an erection I try to not think about it cause it will get bigger an anyone will see it if don't think about it. it goes away it doesn't always happen.
I've felt them through their pants and sometimes if you are swimming with the guy and he rubs against you can feel it too. Some guys seen to be horny all of the time and some of the guys get horny over anything lol.
Look by his pants, by his penis. If something is sticking out, he's got an erection. Unless his pants are 3XL lol I don't think he can hide it. It depends on how often they get them. When a man gets happy, that is what causes an erection