

What you see leading down from your anus is your perineal raphe - here is some detail on that:
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The perineal raphe is a visible line or ridge of tissue on the human body that extends from the anus through the perineum. It is found in both males and females, and arises from the fusion of the urogenital folds.
In males, this structure continues through the midline of the scrotum (scrotal raphe) and upwards through the posterior midline aspect of the penis (penile raphe). It also exists deeper through the scrotum where it is called the scrotal septum. It is the result of a fetal developmental phenomenon whereby the scrotum and penis close toward the midline and fuse
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The hair you have is quite normal - shaving the area can be extremely tricky to say the least - many young women shave the entire ano-genital region, so there is a topic of conversation for you if you approach it in a light-hearted manner to get the techniques right.
I would warn you that shaving around the anus is too easy to cut the anal skin itself, and is extremely uncomfortable afterwards for a number of days - best leave well-alone.
It is best to only shave your scrotum and the hair at the base of your penis, if you use wet razors for your face, use a one that has gone blunt to use on your genital region, get a quality aftershave balm to apply once you have shaved - make sure to fully rinse the area with warm, never hot water …