Open House: The Great Sex Experiment came back with a bang (literally) this week and viewers were left in shock after watching a 15-person orgy unfold on screen.

Keep in mind that even though the show comes from Channel 4, which has given us odd dating series like Naked Attraction and a documentary about the struggles of being a well-endowed man, Open House has been dubbed the channel's 'raunchiest ever show'.

In case you haven't watched it, the show follows couples as they travel to a retreat and go on the hunt for other people to have sex with.

The idea is that monogamous couples who open up their relationships will leave the retreat with a stronger bond after exploring open relationships.

Channel 4.

In the second episode, which aired on Channel 4 on Thursday (25 May), Chanice, 31 and Richardo, 32, returned after their disappointing attempt at having a foursome - and then a threesome - last week.

The married couple were unable to find someone to join them, however, hope was not lost as their fortunes took a turn for the better this week.

After mingling with a new group of 'guests' at the raunchy mansion, Chanice and Richardo invited everyone back to their room for an after party.

As you may expect, the vibe in the room turned sexual.

Richardo was initially ‘overwhelmed’ by the armours experience, while Chanice had fun with two of the women.

Chanice and Richardo ended up having sex in front of the group while the others watched and the kinky scenes left viewers in shock.

Channel 4.

One astounded viewer tweeted: "OMG a 15-person orgy #openhouse."

Another viewer quipped: "15 person orgy. Will Richardo be the one sitting in the corner by himself? #OpenHouse."

A third viewer joked: "I must report this filth to Ofcom. I’d better watch next week to see if it gets any worse #OpenHouse."

Referencing the couple's awful luck last week, a viewer tweeted: "From none last week to 15 this week. #openhouse."

Last week Chanice and Richardo decided to invite one of the retreat's 'guests' to their room, a woman named Precious, 38, who they mingled with earlier in the evening.

They both were stunned when Precious politely declined their invitation and said she was only attracted to Chanice and felt ‘brother vibes’ for Ricardo.

The couple tried their luck again with 25-year-old Grace, after they had a chat earlier in the evening about sexual preferences. But both Chanice and Ricardo were both turned down by Grace.

Open House: The Great Sex Experiment continues on Thursday at 10pm on Channel 4.