Nearly drowned in a Bulldog during an incipient spinning exercise. Felt ill due to a UAS party the night before and tried, unsuccessfully, to take my mask off before hurling. The subsequent mixture of grapefruit chunks and full fry clogged the mask's valves and, with panic setting in, I still couldn't get the damn mask off. Shortly before turning blue, gravity (assisted by blowing out) eventually took its course and the breakfast cocktail passed through the valves and out the side of the mask. Flown home by the irate instructor (Hi Dennis) with the canopy open a notch. Oh how the groundcrew laughed as they passed me a bucket and sponge.