Does this look OK?
Swamp Spit (Ex):  Bosk giants can spit swamp water combined with their gastric juices at enemies.   This is a ranged touch attack with a range of 30 feet that deals 3d8 points of acid damage.  Additionally, a struck victim must succeed on a DC X Fortitude save or becmoe nauseated for 1d6 rounds.  The save DC is Constitution-based.
A bosk giant can store enough swamp water to spit twice.  After that, it may spend a full-round action to swallow enough swamp water to spit again.  A swamp giant may refill its stomach after only a single use, but may never store more than two uses worth of swamp water.