Had my wingman one day in Korea while we were working offshore down low near the ocean and in the typical Korean hazy and pollution-filled visibility WX manage to get himself airsick. During a turn while we were doing 3k ACM engagements (about all we had the viz for), he puked in his mask and dropped off one of the bayonets of his mask, and went NORDO obviously. I see him in a level duck turn and, not getting any response from him, accelerate inside his turn to form up on him. He's alright, giving me the NORDO hand signal, but it's obviously a knock it off and RTB. I have him lead back so he doesn't have to bother with formation flying, and see him fiddling in the cockpit. Im in close formation, right at about 3 feet off his right wing. He tries to clear his 12/P mask by flipping the EMERGENCY position of his oxygen regulator, and all I see is one second nothing....then the next second, a large glob of puke shoot out of his mask and into his face and all over the front of his helmet. He then sheepishly looks over at me with puke all over his face, and gives the hand-across-mask signal again for NORDO/transmit. I couldn't stop laughing and wish I had a camera at the time. Im glad it took a bit to get back to base, since I needed the time to regain my composure enough to resume sounding cool and attack-pilot-like on the radio when contacting Korean and U.S. ATC.