The air in the Temple of Tash is thick with perfume and incense, supposedly to appease and soothe the Tash so their worship of him won't awaken any bloodlust when they interrupt him. It's an odd, unsettling gesture to Susan--to be so afraid of your own god that you have to sedate him with calming smells so he won't be mad at you for worshiping him.

It's just one more reason why she's really begun to wish they'd stayed in Narnia and never come to Tashbaan.