Males become sexually mature between 12 to 15 years of age. Females become sexually mature a little sooner at around 8 to 10 years of age. Much of the amorous activity between dolphins includes chasing each other around and raking each other with their teeth. Dolphins have a tendency to get lazy looking eyes and lay on their sides, sinking like a log, when they are feeling amorous. This seems to be the height of erotic behavior for a dolphin.
Dolphins are indiscriminately amorous.
They have sex with the opposite gender, the same gender, and engage in masturbation with inanimate objects. They also seem to enjoy buzzing on eachothers' slits using echolocation. It is believed that dolphins may possibly engage in this type of behavior to learn about sex as well as to maintain strong social bonds for many sorts of cooperative activities. Therefore, male dolphins have both their penis and testicles packed inside their body. On mammals, testicles are usually found outside the body since sperm dies at body temperature.