Some stuff to point out for your case:
Folded wings will completely collapse on themselves. The drawing you did is actually a pretty okay in-between fold, but not a complete fold. The end of the wing will fold up under the upper part.
For the stretched out part; you make a common mistake I see among most of the people whom ask for help from me. And that mistake is that you simply just don't add enough feathers. The part that you drew actually makes a pretty nice base layer of feathers, but it needs more to sprout from under them. In general though, it looks like you have a pretty solid idea on how to draw wings, just add another rack of feathers next time you draw them.
The bat wings also suffer from a very similar problem that many other people face. Cartoons and fiction for some reason usually always draw dragons with huge wings that attach lamely at a very skinny point. However, if you actually look at creatures with wings like these, you'll notice that the "skin" part of the wing extends far further then just the area of attachment; usually ending somewhere near the legs or on the legs. If you want your dragon wings to look more natural, you will want to extend the skin all the way down the body to the legs. Otherwise, you will continue to have to practice drawing them more stick like until you can make it look right for your style.
The last tip is that those "rod" looking things that are in the wings are actually their fingers. The hand is at the top most part of the wing, with the thumb usually extending from the top. So that little "extra" finger you added at the bottom of the wing doesn't belong nor make sense.
Here's some copied and pasted quotes from two of my past red-lines about wings (linked above). They go into a little more detail about things in general.
When it comes to drawing wings, both the anatomy and feathers can be separated into 3 sections.
Wings aren't just all feathers and actually have a skeleton that runs through it. Wings are a bird's arms and "hands". And are actually quite similar to ours. For a visual, I drew one up for you, but you can also check out the ref I used for it here. There is the upper arm (the part that attaches to the shoulder), the forearm, and then the "hand". They bend in the similar ways as our arms as well, usually just in more extremes. One thing to be aware of is that the size of each of these parts are greatly different from bird to bird. So be sure to look up references of what kind you want to draw beforehand. A general tip is that the upper arm is usually shorter then the forearm (unlike with humans where it's usually equal). It's hard to describe their "hands", but visualize yourself about to give someone a handshake; From that angle, a bird can bend their "hand" all the way down to the point it folds in on its self. You, most likely, can't bend your hand down very far in that position.
Once you have the basic shape, now it's time to put feathers on it. feathers can also be sectioned off into 3 parts. The 'top" feathers are covering over the actual skeleton part, and are usually small a layered. The "bottom" feathers are usually quite long, and don't have bones running through them. These feathers are strictly for flight, and are the parts that are clipped by those who do not want their pet bird flying away. The last part is the "connecting" section. I personally don't know how to describe this part very well, but it extends over both top and bottom parts and is generally where the shoulder is located. These feathers are usually very small, and I wouldn't bother drawing them individually.
I'm not gonna attempt to explain how feathers fold into each other, so here's a simple gif showing it.
Bat/dragon wings are really funky and something I struggle with, so I'll do my best on this.
The fact that a bird's wings are like our arms still applies here; however, unlike the bird, the finger bones go all the way down on a bat wing. They always curve inward. Not outward, and not straight. Inward.
The skin itself is stretched between each finger, and folds in on itself when the wings fold. You may want to look up references for this. You can barely see this happening on your own hands, but its very slight.
The actual wing, at least on a bat, attach to both the arms and legs; stretching over the whole side of the body. In my humble opinion, dragon designs that also do this look much better. Trying to get your bat wings to attach to just the arms will always make them look weird to me. Of course, many dragon artist do this; so it is possible to make it look alright. However, if you want something more on the realistic side, you are going to want them to go down the side of the body.
