they was telling that 'press A as fast as you can to help GOKU to push the spirit bomb
into kid buu' but there is another way to push spirit bomb press the control pad that will
push the spirit bomb.

They say that you can use any suit or any body part for your increased strength , power ,
endurance and speed , but the ultimate body part is the FORCE SUIT which comes at the end
of the game ( after destroying kid buu )which can increase your strength , power ,
endurance and speed at once. When you get 5 of these FORCE SUITS , equip all of these to
your 5 characters ( GOKU , GOHAN , GOTEN , TRUNKS AND VEGETA ) so that you can hit very
much with power , endurance and strength and allows you to move very fast.

Go to West citys Z-Mart once you've destroyed Kid Buu, and buy it for 30000 Zenie. 

go to kami's look out and then go to this bedroom turn super saiyan and pust a when you
are at the window.