You definitely hadn't expected that, you think to yourself, prodding around the edge of what is apparently the leech's mouth. It's tightly sealed against your skin, and when you turn you can make out a thin seam where it meets your skin. Hoping to get it off you give it a tug, only to feel a blast of pain strong enough to knock you off your feet when the leech bites down harder. Probably would be for the best if you didn't try that again.
Prodding the alien appendage, you can feel its smooth, rubbery surface. It's got some give, though you don't want to squeeze or push it too hard just in case it bites down again. There isn't any pain from it as long as you leave it be, and while you'd think a leech this big would be able to suck out just about all of your blood you aren't feeling the slightest bit dizzy. Just kind of weirded out that you have a dolphin-tail-shaped leech attached to your tailbone.
Now on to the task at hand: getting home. You walk through a thin set of trees, eventually emerging on a familiar street just a few blocks away. Suddenly realizing that someone might spot you, you try (and fail) to hide your tail behind yourself, but fortunately it's still dark out and nobody is even up yet. You make your way to your house, tail dragging along the asphalt all the way up to your driveway, then get inside.
Having finally made it back, you head for your kitchen to get the foolproof leech removal solution: salt. There just happens to be a mostly full box sitting in your pantry, and you waste no time pouring the whole thing on the leech... only to watch it all roll off onto the floor. Of course it wouldn't have the same kinds of weaknesses as a normal leech. No, that would be TOO easy.
Exhausted, you sit down on the floor (you couldn't fit in a chair with that thing behind you) and start prodding mindlessly at the parasite. It looks like it belongs on a pooltoy, you tell yourself with a sigh as you examine it from its broad fin to the point where it joins with your body... hey, hold on, wasn't there a seam there before?