A phrase used in surfing to describe the act of generating "ridiculously sick" amounts of spray while intercepting the lip of a knarley wave. This act is usually accompanied by a harsh "whaa POW!" or "Ayeee YA" followed by a light shower or an even more pleasing crash of water.
"Holy SH&t Bra that grom just threw buckets!"
"Dude! you just threw buckets of that lip so hard I thought it started raining"
" That was a sick sesh bro! you were "throwing buckets"!