Q: I saw that it is an achievement and would like to complete it. I always choose a best answer. Thanks in advance!
A: good question, i just bought the game, i love it, and had been trying for a long time to do this. after you score a touchdown, you will still have full control of your player, do not press any buttons, and use the left joystick to run towards your mascot, who is usually on the side of the endzone, during this time make sure you never run out of the endzone. then once you're in front of the mascot you will automatically celebrate with him. but before you try this make sure your mascot is even at the endzone that you are scoring in, as he may still be at the opposite one.