Or search: arousal, hugging, kissing, petting, necking, cuddling, snogging, caressing, smooching, snuggling, stimulation
2 Syllables: SU
awning, bombing, bonding, Brahmin, calming, dawning, fawning, flaunting, haunting, launching, longing, prompting, taunting, thronging, Unwin, wanting, yawning
3 Syllables: SUU
competence, competent, Congressmen, conjuring, conquering, oncoming, pondering, sauntering, sponsoring, squandering, wandering
3 Syllables: USU
belonging, desponding, prolonging, responding
4 Syllables: USUU
preponderating
4 Syllables: UUSU
corresponding

Found 34 words across 5 groupings. Skipped 5 excess words of a similar stem.