problem with germinating

i have a friend that germinated 2 seeds (on separate occasions) by putting them in a damp, folded paper towel, then putting that in a sandwich bag, and put the sandwich bag in his desk. both seeds were fully germinated after only 1 day, and are both currently growing in their own pots. i tried the same method but im having problems... heres how it went for me:
end of day 1: seed opened up
end of day 2: tiny dark green tail-like thing started coming out, but was smaller than the white tail-like thing that i've seen in pictures
end of day 3: tail-like thing retracted and seed started closing
end of day 4: seed almost completely closed, but i can still kinda see the tail-like thing
Note: neither of us have any experience growing, but we did a little research

iv never had a seed thats cracked open then started to close lol. As soon are they opean and u see the white root pot it mate and then ul on ur way

did you stop spraying it and keeping it damp? i have never heard of a seed closing back up... weird :O

i always made sure it was damp, and the root wasn't white and wasn't as long as it should be. maybe its too cold.

it still looks the same as yesterday so im just going to try to plant it. if anyone knows whats going on then please still post for future knowledge.

keep it moist , warm & dark -not 2 much water,just moist,when they get about 1\2 inch to 3\4 of an inch ready 2 plant.24\7 light is how i do it after planting.