“What is gratification disorder because I think my nephew might have something like that”
Gratification disorder is also known as infantile masturbation.
It is common in children between the ages of 3 months and 3 years. It is believed the around 90% of boys and 50% of girls engage in this behaviour. The condition is called a ‘disorder’ but in reality, it is a normal behaviour in young children and disappears with age.

Children with gratification disorder have episodes where they rub and stroke their genitals against a hard surface. They appear flushed and may sweat a lot. They may make sounds like grunting, and they may zone out. They have jerky spams, do repetitive pelvic movements, and rub their thighs together. They can happen anywhere: in highchairs, car seats, their cot, or on the floor. These episodes tend to appear a few times a day and last for a few minutes. They finish when the child is distracted.
One problem is that because the child does not directly touch their genitals, it is not always clear that they are engaging in masturbation and sometimes parents and professionals confuse it with epileptic seizures. The difference is that a child engaging in masturbatory behaviour will stop when he is distracted, whereas an epileptic seizure will not.
If your nephew is engaging in this behaviour, it is a good idea to record a few episodes and take them to his doctor, so he can evaluate it. In general, parents and caregivers are advised to ignore the behaviour or to distract the child. In some cases, children may have issues controlling their impulses and developing their executive function skills and therefore, behavioural therapy and/or medication may be considered.
I hope this information helps! Good luck to you and your nephew.
Lots of love,
Ana