Coming of Age & Growing Up scenes (about boys and girls):
sensitive material below this line about the male sexual organs.
During puberty it is normal to get sudden erections. This may happen if you touch your penis, if you get excited because you see a girl, or for no reason at all.
Start of the process. The penis is beginning to swell. It also gets longer but has not yet begun to rise. You may feel your pants getting tight:
Stage Two. The penis continues to get longer and wider. Now it rises up and becomes ready for intercourse: