Anyone who has ridden a motorcycle around a curve has counter steered. They just might not be aware of it.
The idea is to consciously counter steer to give you more control than just trying to lean the bike and let it happen.
But here is the important thing. Don't look where you're going. Look where you want to go. This is important.

If you can see around the curve, look around the curve to where you want to end up.
If you think your going a little too fast in a curve and start drifting into the oncoming lane and if there is a car in it, do NOT look at it or you will hit it for sure. Keep your head and eyes pointed to where you want to go, and consciously counter steer, and the bike will go there. If you're focused on the oncoming lane in a curve, you cannot make the curve in your lane. This is called target fixation. This a very weird phenomena, the bike will go where you look.
Target fixation can also be a good thing when you use it to your advantage by looking where you want to go.
This doesn't mean that you can't scan for deer or other hazards, but just don't focus to long other than where you want the bike to go.

I ride about 20 miles on a very curvy road to get to town, and when I was first learning how to counter steer, I was nervous in the curves, and had to pull over now and then to let cars pass me so I wouldn't hold up traffic.
I just practiced looking ahead in my lane and counter steering in the curves, and it wasn't long until I could take those curves at any speed I want.

This was the best advice I got in regards to riding in curves.
Just remember: Head and Eyes, and Counter Steer. and you'll be riding the curves like a pro.

Here is a short clip from Ride Like Pro, Jerry Paladino:

 

I'm sure you're a badass on the Vespa forum but it seems to me you're the only one trying to "posture". You gave no advice that hasn't already been given by the guys you're insulting. You've been here a month and think you know these guys? Some of them put more miles on in a year than you will in 5 or more. Get a clue

OP - there has been some great advice given and I have nothing further to add other than emphasize that you take the MSF course. It will give you a good platform for your basic skills and help your confidence (which you are lacking). Good luck

 

It took alot of courage to come to this forum with your issue and honestly ask for help. Despite the fact that most of us, in our heart of hearts, want to be smartasses, usually earnest requests for assistance are met with a majority of people trying to be helpful. You've received lots of good advice here. I know you will be able to put it in practice.

Ride safe!

 

It's just as important to look down at the corner road conditions as it is looking through the turn. In country riding you have to watch for kicked up gravel as your approaching and entering a turn. It is also important to use your head. I'm more likely to take a twisty road faster if I know the road then one I've never been down. Like many have already said, drive within your comfort zone. I always take the curvy routes whenever I have the chance. I've been riding for over 35 years and I still go to an empty parking lot and practice tight U-turns every year. Always remember your greatest piece of safety equipment is what you have between your two ears!

 

I didn't read the entire thread, so this may be redundant. An old greybeard told me this some 30 years ago, now I'm the greybeard telling you. As long as the tires remain in firm contact with the asphalt, your bike can maintain more curve and speed than you are likely to throw it at. The only things that can negate the adhesion factor are road debris, and lean limit. I was riding a lowered bike, and he said "I'd put a lift kit on mine if they made one" I get it now. So as long as you don't corner in gravel, and don't drag your frame, you are unlikely to exceed your bikes limits in a turn. Sure enough, 30 years later, I'd say he was right....

 

Look where you want to go not we're you're afraid you're going. Relax and have confidence the bike can handle the turn and the limitation is you. I've seen more guys go off onto the shoulder or cross the double yellow from target fixation instead of looking where they want to go. Breath, shift your body for the turn, be smooth after sometime going through turns at speed can be a Zen like experience.

 

Only limitation I have found is lean angle. I can't corner as fast on my Heritage without scraping the boards. I don't mind doing that but once I dragged the support. That scared the crap out of me! I think you'll find the bike can handle the corners and you'll just have to slowly push your speed and gain confidence.

 

Courage to be anonymous and ask complete strangers you'll probably never know for advice? He rides with friends who have 30 years of experience and was afraid to ask them. I think we have different definitions of courage.

 

Couple observations. You say "all of a sudden" and "not prepared for it". This is problem number one. You are not looking nearly far enough ahead. When driving ANY vehicle it is important to scan far ahead of where you are so that you can ANTICIPATE what you will need to do. The rule of thumb is twelve seconds. Scan and see everything that may affect you over the next 12 seconds. This includes traffic, wildlife, pedestrians, road conditions, etc. Obviously as your speed increases, the distance that you will cover in 12 seconds increases also and your range of visual scanning must be increased as well. On some very tight curves, obviously you won't be able to see 12 seconds down the road, but as a general guideline, if you can't see 12 seconds ahead, you are traveling too fast for conditions. If you practice scanning this further distance, a gentle bend in the road should not sneak up on you. If you ANTICIPATE the turn, you will be prepared to position your bike properly in the lane to select the right line to execute the turn. Easy peasy.
Secondly, as has been mentioned, you're struggling with target fixation. You see the guardrail, you think "I better not hit that guardrail", and you fixate on that guardrail. When you fixate on it, you stare at it, and when you stare at it, you head right towards it. No good. Instead of focusing on what you want to avoid, it is paramount that you focus on where you want the bike to go. Once you've started to develop the target fixation habit, this can be easier said than done, but trust us. It is absolutely what you must do. Turn your head and eyes and look down the road in the lane you want to be traveling in.

 

Yeah, good point. I should know better than to try to be nice. It's counter to my nature and I'm obviously not very good at it.