Is washing my penis and scrotum and around them a sin since I am touching them?
"And those members of the body which we think to be less honorable, on these we bestow greater honor; and our unpresentable parts have greater modesty, but our presentable parts have no need" (I Corinthians 12:23-24).
As we mature, we realize the significance of our genitals. Where as a child we dressed for warmth or because our parents told us to, as we reach puberty our innate sense of propriety becomes active and we naturally hide what we are embarrassed to think about.
Touching your penis, especially early in adolescence, is a shock as feelings you didn't know existed suddenly flood your mind. If you were raised as a Christian, or at least with Christian principles, you know that sex outside of marriage is sinful. Yet a seemingly innocent matter takes on new meaning and awakens desires that you are uncertain are proper.
First, understand that desires for sex is normal. It is how God designed your body. It is how those desires are expressed that can be wrong. Satan uses your desires to tempt you into considering having sex outside of marriage. The desire for sex is neither right nor wrong, it is lust for sex outside of marriage which is wrong (James 1:13-16).
Touching your penis is not a sin. It would be difficult to use the toilet or dress if merely touching your genitals was wrong. Fully bathing would be impossible and every man needs to wash his entire body, including the genitals. Not washing will lead to problems with odors, jock itch, and skin diseases. If you are uncircumcised, you need to gently wash underneath the foreskin to keep the smegma that there from becoming sticky and causing problems with erections. Under the Old Law, an Israelite was required to wash every time he had an ejaculation. "Now if a man has a seminal emission, he shall bathe all his body in water and be unclean until evening. As for any garment or any leather on which there is seminal emission, it shall be washed with water and be unclean until evening" (Leviticus 15:16-17). This was in addition to normal bathing.