Pluck a string with the right hand then press it to create an upward slide to the desired pitch. May be abbreviated as Shàng huá 上滑. Ferguson offers the variant Shàng huá yǐ yīn 上滑倚音 “Upward Appoggiatura”. It’s an upwards huáyīn used for faster rhythms, often as a grace note.

Ferguson also offers Hòu huáyīn 后滑音 from Source C but does not offer a description.