Hello ther! I'm new here and its glad to meet ya'll. I will now show you how to do this, mainly because some people can't play with picks(Like me xD!), So if you've ever wondered if this was posible let me be the 1st one to tell you IT IS! It's pretty easy when you get the hang of it. At first, like whenver you start learning how to do these pinches, you get some 'pluck!'-kinda sounds, that's normal. The thing to this trick is to follow the same principle as if you were holding a pick. In this case, you will put your Thumb and Index fingers as if you were holding a pick, it may require you to have a bit of long nails, but even short ones can handle it. You have to pick the string with your nail or finger, while having the thumb right behind it, pick the string and let your fingers go below that area so your thumb can get a slight touch of the string. After that quickly put your fingers away of the strings, you need to practice this exercise til you get that screeching sound. After you manage to get that sound, follow up to make some vibratos or bend to help keep the string vibrating. In my personal opinion, lower strings are harder to make pinch harmonics with, but soon enough you'll be pinching all of them xD!
Note: Use heavy distortion, Bridge Pickup, and Tone on the max level on your guitar. It helps produce a great screeching sound when doing these artificial harmonics.
Any questions feel free to ask. If you want me to upload a video on youtube, feel free to ask too ;)

Rock On!!