If you don't pack the rice tight enough, it will crumble when you eat it.
If you don't pack the rice hard enough with your fingers, it will fall apart when you're eating.
ーIf you don't pack the rice tight enough, it will crumble when you eat it.
「米をしっかり握らないと、食べるときにボロボロ崩れてくる。」
pack the rice tight enough で「米をしっかりと握る」
crumble で「ボロボロに崩れる」
ーIf you don't pack the rice hard enough with your fingers, it will fall apart when you're eating.
「米を指でしっかり握らないと、食べているときに崩れてくる。」
pack the rice hard enough を使っても「米をしっかり握る」と言えます。
fall apart で「バラバラになる」
ご参考まで！
カナダ 
