Books like The Threesome Handbook
Vicki Vantoch
The Threesome Handbook is 384 pages, about 7 hours 2 minutes at 250 words a minute.
12 books to read next
How long each takes
The Kama Sutra 3.5 h 
The Joy of Sex 4.6 h 
The Ethical Slut 5.4 h 
My Secret Life 9.4 h 
Ratirahasya 3.2 h 
The Autobiography of a Flea 3.5 h 
Dear G-spot 4.6 h 
The History of Sexuality 3.5 h 
A History of Orgies 4.1 h 
Sex at Dawn 7.3 h 
Understanding Human Sexuality 12.1 h 
Human Sexual Response 6.7 h Bar height shows length. Estimated at 250 words a minute.