"You inhaled it. The person came up behind you and made sure it was close enough to you to inhale which you were sure to forget doing. One of the best effects of dreamweaver is when you are exposed to it again, the fabricated dream, memory, or nightmare raises to your conscious and you believe you are there. Like you believed the Death Eaters were here with the two of us. A wizard or witch can overpower dreamweaver though."
"I know."
"You know you inhaled it?"
"No, I know what the effects of dreamweaver do. I wasn't exposed to dreamweaver."