Word "riff"

[Bassim]

I've tried to use "riff" in my sentences. Have I made any mistakes?

The President is famous for his long speeches in which he often riffs about different topic, ranging from sport, music, arts to health care.

The writer's riff about his failed love affairs was received with a burst of laughter from the audience.

 

[Tarheel]

I've tried to use "riff" in my sentences. Have I made any mistakes?

The President is famous for his long speeches in which he often riffs about different topics, ranging from sport, music, arts to health care.

The writer's riff about his failed love affairs was received with a burst of laughter from the audience.

I looked up "riff". It's used in music. It's also used to refer to remarks made by a standup comic. It would probably be understood in your sentences.