This is a fine peace of magic trick I learned a couple of years back. You might not get it perfect at first, but with training, you’ll get much better pretty fast.
First thing you need to do, is to have your hands free. In this case, we’ll be “removing” your right index finger, but it can just as easily be done with the left one (which hand you use is irrelevant, but I guess it’s easier to “remove” your finger on the hand you write with). Now, take your right hand and hold it like if you were to shake hands with someone, but only let yourself see your palm. Still with me? Good. Now, take the index finger, and make it go in a 90 degree angle (if you understood the part about the palm, then the finger should now be pointing at you). Now you’ve done everything you need to with your right hand.
The left hand now needs to be doing some work. To explain how your hand is supposed to look like, make it first look like you’re grabbing for something. Then, make your thumb do as much of a 90 degree angle towards your left hand’s palm as you can, and then try to cover the knuckle you’re now bending with your left index finger.
Now both of your hands are in position. If your left hand is hurting a bit or feeling a bit weird, it’s normal. Just remember that you won’t be doing this for a long time per performance. Now to the instructions. Take the left hand, and let the thumb rest on the space left on the right hand from you changing the angle of the right index finger. This is to make it look like you’re removing half of your right index finger. After this has been done, simply let the thumb slide on the space left by the right index finger.
And there you go! If you’ve understood every part of the way correctly, it will now look like you’re able to remove your right index finger!
See illustrations below to see if things have been done correctly (as this requires both hands, I couldn’t take a picture of the actual magic trick, only how I meant the positions of the hands should look like):
(open hand, palm facing towards you, like if you were to shake hands with someone)
(right hand open, palm facing towards you, index finger in a near 90 degree angle towards you)
(how your left hand should appear towards others)
(how your left hand should look like from the side)
(how the left hand should look like to you)
Hope you liked my tutorial and that you enjoy this little magic trick for many years to come (I know I will)!