Jewel,
I will leave it to the really brilliant minds to give the "correct" answer but here is the first thing that I can think of.
1. Make some place dark. ALot dark.

Closet, bathroom... somewhere. Test it by sitting in your make shift dark tent for 5 minutes. If you cant see your hand in front of your face its dark enough. If someone walks in on you just sitting in a dark closet, point out that none of us gets enough time for quite reflection in this hectic age.
2. Wash your hands. Dry them. If you have them wear some of those "bootie" gloves. The ones that are white cotton and dont fit. The point is to knot accidently print the film.
3. Get your camera. And go the the quiet dark place. If you have had trouble getting a trully dark place of your own where you are certain no one will walk in on you. Take a large duffel bag with you to act as a dark/black bag. In total darkness (by touch) open your camera and remove the film cannister. Put it where you can get it again.
4. Grasp the end of the film. It may have sprung and wound its way somewhere on the backside of the roll. Fish for it gently. If you are at the end of the film there is likely not a picture to ruin with prints. but be careful in case. Pull the film off the take up. You may need to activate your camera's film rewind function to get the take up spinning.
5. When you have the film in your hand. (Dont loose that end.) Fumble around for the cannister that you have forgotten where you laid. Holding the film be the edges feed it in through the little felt brush on the film cannister. It may take a few tries but it can be done.
6. When you have it threaded just keep gently threading by the film edges. When the last bit goes in congratulate yourself.
7. Now if the film broke (not likely, but possible) you may need to take it to a professional lab and tell them the film broke. If it just pulled free of the cannister (most likely) just have it developed where ever.
Hope this helps. The only other option too feeding it through that little crack is to pop the top off the cannister. Doable but more involved.
Cheers. Goodluck.
Ty