"It seems this is quite normal for some cultures, according the instructions of DR.suchitra in her blog:"“A guide to teenagers parents” - A mothers role.
The article had some interesting points and some weird ones as well. I don't know if it would appropriate for a parent to show their son or daughter how to masturbate although some families do engage in incestuous relationships but the vast majority of families do not!
However I do believe there are certain things parents need to teach their children when talking about bathing such as anal and genital cleanliness. Daughters should learn how to use a douche to help out when she has her period and sons should be taught how to properly clean his penis and testicles, especially if he's uncircumcised. When a foreskin is not pulled back to clean the glans there's a lot of bacteria that can build up which could cause problems in the future. I've heard that circumcision became popular in America to help prevent masturbation, probably because they felt there wasn't a need to show a boy how to pull back his foreskin and that way he wouldn't become aroused. Guess what, a boy's going to discover masturbation no matter what! I suppose there are some parents who fear their son might become aroused when being taught how to clean under his foreskin but the parent should understand that a young man becoming aroused is completely normal and is nothing to be embarrassed about.
Also it helps if parents are open when talking with their children regarding sexuality. What if a family never talked about sex and then a teenager has a sexual experience with someone and ends up getting a rash or some STD, if they're not open about discussing sexuality then the teen might be too embarrassed to tell his/her parents that they need to see the doctor and their situation could become much worse.
One thing I found interesting in the article was when it talks about masturbation helping to relieve violent behavior, I don't know about violence but I do know that typically if a male ejaculates and has an orgasm it takes away some of his sexual tensions. I know that's the case with me, if I haven't ejaculated in awhile I feel like I'm always thinking about sex but if I have an orgasm I tend not to think as many sexual thoughts as often. I think I first became aware of that when I saw the movie 'There's Something About Mary' where Ben Stiller's character masturbates before going on a date with Mary and she thinks he has gel in his hair but it was actually his semen. After watching that clip it gave me the idea to masturbate before hanging out with people I was attracted to and I think it did help relieve some of my sexual tension.
And then there's another topic, the sexual scandals of Catholic priests and choir boys, I know it's quite a leap from the article but I just wanted to put it out there. I think priests should be allowed to marry and be able to have a healthy sex life. We are all sexual beings and when you deny a person to enjoy their sexuality with others bad things happen from child molestation to rape. Look at prison rape for example, I've heard some people ask why are there more homosexuals in prison than heterosexuals, I think they're trying to claim that homosexuality is evil but they miss the point. When you put only males or only females together people are going to try to fill their sexual needs, it doesn't mean that they're homosexual but it's their only sexual outlet besides masturbation. Although prisoners sometimes can have conjugal visits from a spouse and that was probably started to help reduce the amount of rapes in prisons I would imagine.