Theliel is named with Anael and Donquel in Arthur Edward Waite’s The Book of Ceremonial Magic.
A collective address
Chapter VIII, section 2 reproduces an invocation addressing these names as princes of love, together with their ministers. It attributes the arousing of love to those addressed.
The passage occurs in Waite’s presentation of an experiment from the Book of True Black Magic.
Source
The Book of Ceremonial Magic, chapter VIII, section 2,“Concerning Venereal Experiments,”printed pages 300–301.