He raped her. His will wasn't affected by the aphrodisiacs because he is a demon. She screamed for him to stop and he didn't. He didn't ask, he just threw her down and had his way. In the novel it's EVEN more apparent (although it's pretty clear in the webtoon as well). Someone under the influence can't consent and she literally said no. It's quite worrying that you don't consider this rape.
Even the synopsis mentions that he takes her by force.
It’s rape through and through he literally drags her out
Idk I see a lot of ppl saying she was raped so I think he rapes her in future chapters maybe? But if it’s the first chapter it’s like they was both under the candle aphrodisiac and like she pulled him and kissed him first so I can’t fully place blame him. However I did read some spoilers and he’s apparently stills pos so ╮(￣▽￣)╭