Fuck it, I'm in brother. I suffer from either SBS (small bladder syndrome) or HEKD (highly efficient kidney disease), and am endowed with a device that has a chamber long enough to cause multi-directional urine flow (also known as "split streams"). I have not modified this device in any way (I have a friend who's familiar with Prince Albert, he has no option but to sit when he nature calls, but makes a great fire extinguisher should the need arise).
On to the topic at hand.
After sex (solo or with partner(s)) - suck it up and sit; there's no controlling things when the chamber is cluttered or restricted by other fluids. Personally I prefer jumping in the shower to clean up and just let things follow their natural course; sometimes its invigorating enough that you can proceed to round 2. Also remember, there's only two types of people - those that piss in the shower and dirty fucking liars.
At home - sit if you don't have a maid or like to clean up the floor on a fairly frequent basis; the mood will be killed if your lady friend comes over and sees urine all over your bathroom floor/toilet seat (you're at least lifting that right???) In general I sit in the bathroom I share with my SO and use other methods in the other bathrooms around the house. She appreciates this.
Anywhere you're not sitting:
Phase one; judge the amount of delivery - highly important. I find that the fuller the bladder the stronger the stream; oddly the stronger the stream the less likely to have a strange splatter pattern - once the flow starts at least. Being prepared for the initial surge is the key to a successful conclusion!
Phase two - this phase is pretty crucial; It takes a moment for the entire chamber to be filled with the exiting liquid. If the initial surge is from an underful bladder it might be weak - causing extra turbulence and an increased risk of splatter. The "squeeze and release" method helps here - ideally you want to allow the chamber to fill completely except for the last bit and then allow the flow once this procedure is complete. This has an added benefit of a shield - yes you might splatter your hand a bit but that is SO much better than soiling your pants/suede shoes/monocle (it happens). Urine is sterile and you are washing your hands after this procedure right? I assume if you're concerned about urine in general you're from a place where hand-washing is the norm.
Phase 2a - if you're not at a urinal you can also do the wide legged stance method. Getting the barrel closer to the target significantly aids delivery. Stand with a really wide legged stance - bracing your feet against available walls/bathtubs/showers so that you've got a solid starting position that allows you to get better access to the bowl. Personally I use this method at friend's, in-law's, and family's houses - anywhere when I'd feel weird thinking that these people might end up having to deal with my splatter. Honestly while dating my SO I sat at her and her parents house; because damn I'm not going to be that guy. Yes they will know especially if they went through the effort to clean for company.
Phase 3 - the tapering off. This tends to be less risky than phase 2, but don't get cocky! Generally lean in at this point; as the flow reduces there's a risk of extra turbulence; however this turbulence will have little force - if you lean forward a bit to allow gravity some control you should reduce any additional spray to a minimum!
Phase 4 - the finishing touch! You've made it! Just dribbling at this point! However the DANGER IS STILL VERY REAL!!! In fact this is probably the most dangerous phase; as it doesn't really matter the design of your personal device - flailing will cause catastrophe! Successful closing method - shake down, lift up. Shaking all over the place will cause problems - again you're using gravity as an assist here - so efficient even NASA uses this method for satellites and space probes (and you've got a most delicate space probe in your hands at this phase amiright???). Shake down, lift up, Shake down, lift up. I know there's an old joke about more than two shakes is playing with yourself. This is not true Hell you know when you're playing with yourself and right now you're doing serious business. Repeat steps 1 and 2 (shake down, lift up) until you're at your personal comfort level. Consider your undergarments as well - silk requires a far more cleansed device than cotton or high-tech material - but understand that things are never completely dry.
Phase 5 - wash up. Just do it. I mean jesus; wash your damn hands.