I was out Sat & Sun practicing small jumps. I've never done a jump before, but want to learn. Sat. I was on flats and successfully did a small jump twice, each time with my front foot sliding off the pedal. Now, I know what my problem was, I was not keeping my heal down. Sun. I went back and tried this with my clipless pedals. I successfully did the small jump the first time, obviously not falling off because I was clipped in, but I did notice my foot was in the same position as the day before. Then for some reason, I chickened out and could not attempt to do the small jump again! Why does this happen. I get this mental block and then I can't do it again, even though I just did it successfully the first time? Second questions, how do I force my heal down so when I try again on flats I don't slip off the pedal?