Just some funny/sexy starters where one or both of the muses involved are some kind of monster! I tried to keep things vague so it's mun's choice as to what monster you are! (feel free to add more if you want!)
"Don't you dare bite me, you --!!"
"Holy shit, is that what you really look like?"
"Why do you smell so good?"
"I don't care how many you have, just take me to bed."
"Well, I didn't consider fucking something like a squid *before*..."
"I know you're hungry, but I'm not food."
"Okay, let's just get home before this gets any stronger..."
"I can't help it, you're so soft..."
"I don't care if it's wrong, I'm fucking it."
"You ever wanted to be a [mom/dad]?"
"Great, now my [mom/dad/rommate] thinks I'm into bestiality."
"Aren't you frightened of me?"
"I've gone beyond scared and entered the realm of 'strangely turned on'."
"You ever wonder if you're gonna look back at your life and be ashamed of what [you fucked/let fuck you]?"
"I'm not sure if it's gonna fit, but my momma didn't raise no quitter."
"Sorry, was I supposed to be surprised you're a [species here]?"
"... I was hoping for a better reveal."
"Fuck me... no, really, fuck me!"
"That's definitely not normal..."
"I need someone to carry my [offspring]."
"I'm offended that I wasn't your first choice to carry your [offspring]..."
"Great, I've got sucker marks all over me."
"I can see the headlines now: '[Man/Woman/etc] meets an alien species -- Welcomes it to Earth by fucking it.'"