However, the representative insisted Mr Musk had not witnessed or participated in any raunchy behaviour.
The spokesperson said Mr Musk had attended in the mistaken belief the event was a "corporate" costume-themed party.
The statement claimed Mr Musk left at 1am and had spent the previous hours discussing "technology and business".
"Elon was at the party for a couple hours and left around 1am after talking with several DFJ-funded entrepreneurs about technology and building companies. His impression was that it was a corporate party with a costume theme, not a 'sex party', and there was no indication that it would become one after he left," the statement read.
In his blog post, Mr Biggar said he had not witnessed any sex or drug taking at the event either, which he described as "a top-tier VC [venture capital] firm's official party".
"I don't want this to be anticlimactic, but I didn't see any sex or drugs," he wrote.
"I went home at 12:30am, and I guess sex parties don't really kick off until the boring f-ckers go home.
"I didn't exactly know it was a sex party, and I got bored at some point and went home."
But Mr Biggar said that while the event was not officially described as a "sex party" by hosts, it was obvious that racy behaviour would be on the cards.
He wrote: "This wasn't billed as a sex party; it was official party of the VC firm. But we were certainly primed for it — there was a sorta 'wink-wink, nudge-nudge' thing going on.
"We were warned before going not to be freaked out about the stuff there, no photos were allowed (!), and definitely don't tell anyone what we saw. I actually texted my co-founder 'I think I got invited to a sex party'."
In her book, Chang describes the "toxic" culture within the US tech industry and its exclusive sex parties, chauvinistic attitudes and emphasis on hedonism and excess.
According to Chang, a typical Silicon Valley sex party had a strict guest list with security guards at the door.
The events are either catered or guests cook dinner together and alcohol is widely consumed, followed by drugs after the meal.
The most common drugs are "some form of MDMA, a.k.a. Ecstasy or Molly" — and some pills proudly display the logos of high-profile tech companies.
Guests then start "cuddling and making out" and guests will break off into "twosomes or threesomes or more".
The parties last all night before guests reconvene for breakfast, "after which some may have intercourse again. Eat, drugs, sex, repeat."
However, according to Chang, while the women involved in the so-called "cuddle puddles" are willing participants, there was a clear power imbalance in play.
She argued that some women's careers had been damaged after participating in the debaucherous behaviour.
"The problem is that weekend views of women as sex pawns and founder hounders can't help but affect weekday views of women as colleagues, entrepreneurs and peers," Chang wrote.
