• didning,
• dialling,
• tiddying,
• riddiling,
• fiddleing,
• fidling,
• fidiling,
• diding,
• dwidling,
• fiddiling,
• woddling,
• widdling,
• dieding,
• ideling,
• idiling,
• kiddling,
• deadling,
• fideling,
• diedline,
• didgging

• cuddling,
• Dialing,
• Paddling,
• Saddling,
• meddling,
• peddling,
• idling,
• Muddling,
• fiddling,
• Huddling,
• deadline,
• Waddling,
• Riddling,
• doodling,
• Titling.

The adjective form of the word "diddling" is "diddling".

The plural form of the word "diddling" is "diddlings"

The singular form of the word "diddling" is "diddling". The word doesn't typically change when going from plural to singular.