i usually tell my folks to stop being so grabby. don't grab. think of arms as sword. sword cuts. watch Endo sensei's hands. he doesn't like to grab.
https://www.youtube.com/watch?v=mHxBVgN8pwU
https://www.youtube.com/watch?v=nkA8uA_kwyA

Also, grabs meant your arms are locked, i.e. useless for striking or doing other stuffs if uke decides to do something else.