Hi Bill, I replied to this thread a few months back extolling the virtues of cisc. It really is such a life changer that it is worth persisting. Anyone else reading this post who is a little squeamish may find it goes in to more detail than you want, you certainly won't want to read it whilst you're having your tea.
You are right about the need for three hands. I'll try and give you some tips.
My caths are 14f I think 18f would be a challenge.
I am using HiSlip plus. I assume yours are the same or similar.
Once you succeed your going to get a lot of urine flowing out of the cath if you get it wrong that could be going over your carpet or sofa so best do this in the bathroom.
I don't know whether you intend attaching a bag to the cath, I think we did for the demo but in practice I think you will just want to be able to use the cath on its own and hopefully get the urine down the toilet without having to manage the bags as well.
Forget about aiming for the toilet, as any woman will tell you, us blokes have got a bad aim at the best of times, add in the complications of the cath and your aim is anywhere.
So put an old bowl in the bathroom washbasin this is about waist height which means you don't have to aim far when your standing right next to the sink and any which misses the bowl you're going to just have to turn the taps on and wash down the sink.
Next sit on the edge of the bath, I find this a bit better than sitting in a chair which is a bit too low, and easier than standing which is a bit too tiring if things are taking there time.
Get the cath lubricated and out of its sachet. It has the bag end which is green (maybe different colour on an 18f) plastic, the bladder end, and in between a wrap around blue sleeve. Ideally you only want to touch the bits which aren't going in your body, the rest is slippery and will be going inside you so you don't want to contaminate it.
Sit with you thighs clamped together this should make your penis jut out a little. Left hand holding the bag end of cath with a finger or thumb blocking the cath exit hole, you'll only take that finger or thumb off when it's fully in and you're standing up and pointing straight at the bowl.
With your right hand fist gently around penis, but thumb and forefinger just above head of penis holding the blue plastic sleeve gently and guiding cath down eye of penis. You should manage about four or six inches with ease, then you have to get around the bend.
Left hand should keep applying pressure but not so much that the cath just flexs and bends. Right hand fist should be supporting penis to stop it bending, relax your thighs now, having them clamped will not help the next bit. If possible pull penis away from body a little that way you have to go around a 90degree bend rather than nearly 180degrees.
Now slide sleeve along catheter about half an inch further up than eye of penis keep as much of fist supporting penis as possible grip sleeve with thumb and forefinger as hard as possible so you can use them to push cath in the extra half inch, you have to be gripping hard enough that sleeve does not slip along cath. Repeat this process half an inch at a time.
Best tip I ever had was, if you feel resistance COUGH. I think it just relaxes the bladder muscle for a second.
You should be in in no time at all. The cath seems almost compelled to come out so don't let go of it or penis with either left or right hand. Stand up, go to sink, aim at the bowl remove thumb or finger, relief.
You've not finished yet, stay at sink. Slowly start to remove cath, more urine will then come out from lower in your bladder, keep removing cath, just as the end of cath leaves the eye of penis a little more urine will come out. It's these silly unexpected bits of urine that could make a mess.
Now tip bowl down toilet, tidy up, drink a load of beer so you can have another go. After practice you'll be able to do this sitting on a toilet seat and once cath is in, stand up, turn around and piss down toilet. I still spray a little over the toilet seat but that's just me marking my territory.