The dead-ball expert punched the air after his speculative free-kick beat Schalke goalkeeper Ralf Faehrmann on 84 minutes.
Risse's equaliser added to Leon Bittencourt's strike, cancelling out Schalke's early goals by Yevhen Konoplyanka and Breel Embolo.
"That's one of the saddest goals I have scored in my career," Risse, 28, said. "It's a very emotional mood, because week after week, it's becoming clearer that relegation is approaching."
With just three games left, and Bundesliga champions Bayern Munich still to come, Cologne remain eight points from safety with only a mathematical chance of surviving after three seasons back in Germany's top flight.
Several Cologne players shed tears after the final whistle.
The point rewarded the hosts for coming back from 2-0 down against second-placed Schalke, whose coach Domenico Tedesco slammed their performance.
"Our style was good in the first half, but you cannot play more arrogantly or handle the chances we had with more negligence," he fumed after Schalke wasted several opportunities.