Unknown to Gideon, the smell coming off Sia effectively numbed his senses causing him to be unaware of his surroundings, and for the same reason, he didn't realize that he was squeezing and feeling Sia's tails more forcefully which at the same time caused her greater pleasure.
Sia covered her mouth with both of her hands and and suppressed the sounds that were trying to come out of her mouth, her eyes tightly shut with small teardrops at their corners.
'This, is amazing!' Gideon in his muddled state of mind which was no different from him being drunk thought as all he saw were the three twitching fluffy tails.
(Author: I don't think poison immunity is a thing here since she's technically releasing pheromones. But I could be wrong.)
Sia unintentionally closed her thighs as her back arched. And eventually, she couldn't hold it in anymore.
"Ah~" she accidentally moaned causing the two of them to freeze.