Its not made out of, or even include any penis 99.9% of the time. Of the few instances where the penises of animals are commonly consumed, it is sometimes done by cultures that make use of every single scrap of meat, but mostly is just the result of magical-thinking and the belief that something more than nutrient exchange happens from eating something. The penis is not a very tasty part of the body, it's mostly just spongy tissue and veins that is, by all accounts, rubbery and unpalatable when cooked, regardless of cooking method used.
Sausages, by contrast, are a kind of food with A LOT of variety and most would be considered downright delicious by anyone who eats meat. There are hundreds of different kinds of sausages, and most don't include any penis or penis parts.
At it's base, a sausage is a tube-shaped product comprised of
*mincemeat/ground meat
*spices
*usually has rice/breadcrumbs/potato other vegetable as a filler.
*sometimes the sausage has a "casing" and sometimes it doesn't.
It can be made out of any meat, from any animal, technically. There's no reason it *couldn't* be made of penis meat, but again, penis is apparently just not a very tasty body part. Though there *are* vegetarian/vegan versions, they're just a spin on the original that uses only plants. It's not generally considered real sausage.
TRADITIONALLY, sausage is a poor man's food, which meant poor quality ingredients just stretched to their best use, but today, sausage making is an art all it's own for some, and it can in fact be quite pricey, with very rare and valuable ingredients being used instead.
For the average person, though, making sausage involves getting cheaper cuts of meat plus offal (internal organs) and putting them through a meat grinder, then mixing the meat with various spices and sometimes rice/etc, then packing the meat mixture into a "natural casing" which is a very nice way of saying "cleaned section of intestine" and tying or twisting the casing every few inches to create individual sausage 'links'. If you bite into a sausage and it "pops", that's a natural casing.
Other times, the casing is made of something else. Hot dogs are "technically" a type of sausage, and their casing isn't intestine, it's.. idk, something else. There is no "pop', it's all squish.
I've no idea how uncased sausage is made, to be honest. American "Breakfast sausage" is one of these "uncased sausages", they're lumpier so perhaps they're just formed and cooked as-is? That's just a guess, sorry.
There is one more type of sausage I have deliberately left off till last, and that's because it isn't quite like the others. That would be blood sausage, and it is made of exactly what it sounds like. Blood. ..and spices, sometimes little bits of meat, fat or other things but usually just blood and spices, plus a thickener to allow it to be solid at room temperature.