‘Soft Kitty, Warm Kitty’ song appearances

S01E11 "The Pancake Batter Anomaly":

The song is first introduced when Penny sings it to Sheldon when he has caught a cold.
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S02E21 "The Vegas Renormalization":

Penny had to sing "Soft Kitty" to Sheldon again on the pretense that "...Homesick is a type of being sick" since he had to spend the night in Penny's apartment because he locked himself out of his and Leonard's apartment.
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S03E01 "The Electric Can Opener Fluctuation"

When Sheldon was feeling sad about being betrayed by his friends (and not being able to attend Comic Con), Penny starts singing "Soft Kitty" in an attempt to cheer him up, but was interrupted by Sheldon as he said, "That's for when I'm sick!! Sad is not sick.
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"S03E08 "The Adhesive Duck Deficiency"

When Penny was a little lightheaded from the powerful pain medication and a muscle relaxer that the hospital gave her after she dislocated her shoulder from slipping in the bathtub, Penny asked Sheldon to sing "Soft Kitty" to her (according to her, "Injured and drugged is a kind of sick"). After much prompting, the two sing it as a round.
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S04E02 "The Cruciferous Vegetable Amplification"

Penny sings "Soft Kitty" to Sheldon, or more accurately, Sheldon's Mobile Virtual Presence Device (Sheldon in robot form) after Sheldon falls down the stairs. Sheldon plays "Soft Kitty" on his recorder (woodwind musical instrument) as a round while Penny sings "Soft Kitty".
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S05E06 "The Rhinitis Revelation"

Sheldon's mom, Mary, sings "Soft Kitty" to Sheldon after he gets sick from being in the rain after he felt that his mother was ignoring him over spending time with his friends.
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S06E22 "The Proton Resurgence"

Sheldon sings the song to Professor Proton while the latter is in hospital.
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S08E13 "The Anxiety Optimization"

Leonard and Penny sing the song as a lullaby to put Sheldon to sleep because he hadn't slept in days.
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S10E20 "The Recollection Dissipation"

Sheldon is recovering from both stress and fever brought on by him working on two different projects at once. Amy sings the song to him in three different languages (English, German, and Mandarin) while playing an autoharp.
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S05E18 "The Werewolf Transformation"

Penny mentions to Sheldon that she sings "Soft Kitty" to him when he's sick.
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S01E13 of Young Sheldon "A Sneeze, Detention, and Sissy Spacek"

When Sheldon is sick in bed, Mary sings the song to him.

Here you can find the list of episodes, where Penny sings ‘Soft Kitty, Warm Kitty’.

This is the list of episodes, where Amy sings ‘Soft Kitty, Warm Kitty’.

Also you can check ‘Soft Kitty, Warm Kitty’ lawsuit information.