You have been masturbating for the last seven years. Though it is an easy way to let out your sexual desire and gain sexual satisfaction but there emerge to be no explanation for using a water jet. In the long term it can harm you and may harm your private parts. Feeling of weightiness in the lower abdomen behind the act is another way of expressing your sexual gratification. But I will counsel you to cease from this act and instead deflect your mind. To healthy activities like sports, books, music, etc. it will take your mind away from sexual fantasies.