har rdza bra’ shis rGyal mtshan (Self Arising Threefold..)
Gyaltsen, S. T., Gurung, G. S., & Brown, D. P. (2022). Self-Arising Three-fold Embodiment of Enlightenment: [of Bon Dzogchen Meditation] (English Edition) (2nd ed.). Mustang Bon Foundation.

https://pointingoutthegreatway.org/books-list/the-three-fold-embodiment-of-enlightenment/

Daniel Brown  (Sacred Sundays)
Sacred Sundays with Daniel P Brown. (2019). Sacred Sundays. https://youtu.be/0swudgvmBbk?t=4770

In this interview he mentions how "Pointing Out the Great Way" will also sustain the old Bön traditions of inner fire yoga with a consort

Dr Nida Chenangtsang
Chenagtsang, N. (2018). Karmamudra: The Yoga of Bliss: Sexuality in Tibetan Medicine and Buddhism (English Edition). 978–1-950153-00-8.

https://www.goodreads.com/book/show/40000465-karmamudra

Dr Nisa Chenagtsang describes in this book what used to be secret transmissions of his lineage.

The translator of his book is Ben Joffe, the author of the "Perfumed Skull" blog. The full foreword to the book can be read on Joffe's website.

There are some extensive reviews of the book on the linked Goodreads page

Keith Dowman
Vajra Love - Collection

Downman, K. (2018). Vajra Love - Essays on Sexuality. Keith Dowman, Vajra Love.

http://keithdowman.net/list-of-essays-on-sexuality.html

Drukpa Kunkley´s Sutra of Sex (The discourse on mundane pleasure)
Dowman (Translator), K. (2018). Drukpa Kunley’s Sutra of Sex. Keith Dowman (Archive). http://web.archive.org/web/20200124002155/http://keithdowman.net/vajralove/drukpa-kunley-sutra-on-sex.html

Holly Gayley
Gayley, H. (2018). Revisiting the “Secret Consort” (gsang yum) in Tibetan Buddhism. MDPI.

https://www.mdpi.com/2077-1444/9/6/179/htm#fn050-religions-09-00179

"Tantric texts that detail the qualities of a consort almost invariably take a heteronormative male perspective by detailing the attributes of suitable women according to various typologies" - but she doesn't mention the detail



Ben Joffe, Tantric Sex Partners
Joffe, B. (2016). Tantric Sex Partners, Actual and Imagined. A Perfumed Skull.

https://perfumedskull.com/2016/05/16/tantric-sex-partners-actual-and-imagined-tibetan-karmamudra-and-the-life-and-times-of-lelung-jedrung-zhepai-dorje/

Ben Joffe is also  the translator of Nida Chenagtsang's book.  

Ben Joffe, interviewed on the "A State of Mind Podcast"
Joffe, B. (2020). The Yoga of Bliss: Sexuality in Tibetan Buddhism with Dr. Ben Joffe. Anchor.

https://anchor.fm/a-state-of-mind

Notes

Under age
An important historical note: the requirement to be under 16 must be seen in a context where life expectancy was a  40 years. However, even 16-17 years seem to have been quite mature for a consort:

Keith Dowman translates "it is taboo to make love to a girl under 10" from the poem "The discourse on mundane pleasure