kupaa
Kupaa (くぱぁ) is the Japanese sound effect for spreading something open, most often spreading the labia.
This tag is for the sound effect itself. Use this tag only when the sound effect is present. Do not use this tag for spreading the pussy in general.
On Pixiv, the くぱぁ tag is often used for spreading the pussy in general. This translated tag has been removed as per topic #13162.