guys he seems to be right...and very normal.......if u are seeing ur kids doing this...it doesnt mean they are not.
Quote from medical psychology refrence book online.
________________________________
When does masturbation begin?
Masturbation can occur as early as age 6 months. Then, by 2 or 3 years of age, it is a habit. After that, there is not much change until the onset of puberty. Generally, little boys masturbate by rubbing their erect penis up and down with their hand; other boys grab and pull on the foreskin or glans of the penis. In rare cases, the boy may rub his penis on the floor or his bed. The girls usually stimulate their clitoris. Most of them usually do not know the existence of the vagina, and stimulate those parts that give them pleasure, generally, by rubbing against a pillow, doll, quilt, or a blanket. Often, a child who does not have friends to play with and spends a lot of time alone, may revert to masturbation. If you do not want your children to masturbate, do not scold or scare them into quitting, but be their friend and spend more time with them.
Do children feel a climax also?
Yes, of course they do, but the climax is a little different than what an adult feels. For children, even just the act of pleasuring themselves by genital stimulation, or understanding the feelings they are experiencing throughout their body, are overwhelming at their age. However, boys, especially, experience nearly the same orgasm as do adults in many cases. By puberty, some girls are also able to feel orgasms.
Steps toward reduction
Keep active mentally (arts, creative activities, academic research, etc.).
Keep active physically (sports, etc.).
Keep active culturally (movies, theatrical performances, concerts, etc.).
all and all ...it seems pretty normal to STIMULATE those areas...but it would be a EYE OPENER to walk in on it, or actually be "jacking off" persay...but pillow rubbing or dry humping slightly against things is very very common.
-murph