I’m in a movie frame of mind, so your post makes me think of Mel Brooks History of the World Part 1 where Harvey Korman asks for the “pissing bowl” and beseeches the “pissing boy” to “wait for the shake!”
OMG, this is one of those threads that would have our kids shaking their heads and thinking we’ve all gone mad…
Howcum boys can have contests involving how far et al they can aim but can’t seem to master getting the pee into the toilet bowl??? Decades ago discussion with another woman- male physicians can miss, too. Elongated bowls- always for decades. I prefer them as well.
I like the idea of making the boys clean the bathroom. Either they aren’t bothered by the grossness or they figure out how to make it less gross.
btw- thank goodness I had to go to a women’s floor when doing chauffeur duties when son was in the dorm, I usually found stopping at McDonald’s or somewhere before arriving was indicated before doing apartment pick up.
Kind of unlikely that the OP has seen this, don’t you think?
They should sit at home, and stand in public restrooms. Period. It also eliminates the problem of the toilet seat being left up. DH was raised that way and insisted S1 and S2 do it too - I’m grateful.
I wasn’t responding to the OP. Regardless, I’ve had occasion to clean ladies rooms at a point in my life, so it’s not unrealistic that a woman may have been in a mens room. 
I have that black hand print problem in our downstairs bathroom too. it took me a while to figure out why it ends up there.
Are you referring to the kind of “bathroom time” these gag letters posted in college dorm bathrooms across the country refer to?
Hah, MichiganGeorgia…glad I’m not the only one who sees that!
Madison85, it seems I am indeed. Had never heard of this gag, though. And I’m not joking, either. Not worried about the pipes, as far as the OP has stated the problem is the wetness factor. But as my proposed solution involves access to paper towels, I would want to make clear that these are to be placed only in the garbage can - and that no one will judge when it is emptied.
I have no idea how to edit a comment. I see in my original comment I said, “not to throw the paper towels into the flip-lid garbage can.” That should be “not … into the toilet, ONLY into the flip-lid garbage can.”
I noticed that the OP just joined today. I hope our frank comments didn’t scare her away. She’ll have to get used to us I guess.
Mr. B divided kiddos BFs into sharpshooters and non-sharpshooters. Of course, he would not say a word to the young men or kiddos! But some dads apparently do not keep their mouths shut about this matter. 
Maybe OP can try shaming the young man into adopting better practices at home so he will be spared possible embarrassment at his (future) GF’s homes?
When my son was studying in Berlin during the summer of 2011, he lived in a room that a local family regularly rented out to foreign students. One of the first things he noticed was that in the bathroom designated for his use, there was a sign over the toilet depicting a little boy in silhouette peeing standing up, with a heavy diagonal red line through the picture. In other words, peeing standing up was strictly verboten! (I imagine the family had had some bad experiences with male students!) My son was outraged at this violation of his Constitutional rights as an American male (I think those rights must be included in the penumbras and emanations from the Due Process Clause). So I said to him that he could do what he liked (I doubted that there was a video camera in the bathroom set to record him), but that he’d better clean up after himself. As far as I know, he had no problems.
To be fair, he did tell me that he finds it much easier to empty his bladder completely when standing.
Personally, I haven’t missed the experience at all.
Just saying years ago I toured a model home and saw wall to wall carpeting in the bathrooms. my first thought was ewww…
American men are not going to sit. Forget it. They can’t take the chance that any of their male friends would find out about it. No way.
I would also point out that not all streams are the same (and alas, they can change over time). So some people may have more spatter than others.
Demanding cleanup is the only answer, short of a separate bathroom or a urinal.
I lived in a family of all women for a long time. Rather than forget to put the seat down, particularly at night, I often sit. It doesn’t de-man me and, believe me, I’m perfectly comfortable using urinals. It’s better than having your wife or daughter fall into the toilet at 3AM. That sounds funny but it can hurt both the person and the toilet.
I’d say: you’re 6’6" and you need to either sit down in our house or clean up after yourself every single time you go. As my dad would say, in the service you clean up after yourself so you can clean up after yourself now.
Agree with making all who share the bathroom clean up, and then the other(s) will start paying attention and ask the guilty party to keep the floor clean.
DH is 6’ 4" and thankfully we don’t have that problem. But, hand washing and tooth brushing are another story. He bends over the sink to wet his hands or toothbrush and then straightens up and vigorously brushes his teeth, lathers his hands and shakes off the excess water. We have very hard water and my counters, mirrors and kitchen window are always covered with spots and drips.
An analysis of fluid dynamics in the context of male urine stream analysis including high speed camera footage:
My wife will be brushing her teeth – very neat brusher – and i’ll be standing next to her flossing my teeth. She’ll mumble “doh flig foo ah the mirr” – “Don’t fling food onto the mirror.”
It happens. Now and then the mirror gets a wipedown.