Lucy says: yes!

"Oh, oh! Master! Can I play around with Erza a little bit too?" Lucy asked, raising her hand up eagerly.

Natsu raised an eyebrow at Lucy. "I thought you were a sub?" he asked.

"I'm a sub towards you, Master," she corrected. "I can swing any way in terms of sex otherwise. Even be dominant towards my Master if they want me to be. But I can jump on any potential sexy action my Master allows too..."

"...you really are such a slut," Lisanna noted to Lucy, who turned to her, and stuck out her tongue.

"Yeah?" she replied to Lisanna. "And just what's wrong with that? If you're trying to insult me, you shouldn't do so by stating the obvious."

Lisanna giggled and shook her head as Natsu considered, before looking at Erza. "...do you mind?" he asked her, and she shook her head.

"Not at all Sir, but thanks for asking!" she grinned, getting up and walking to Lucy, and kissed her. Natsu took a moment to watch, before turning to look towards Lisanna.

"So... While they're having fun... Wanna just cuddle, or perhaps do some more fun things too?" he suggested, and she grinned, and sashayed over to Natsu.

"We can just cuddle for now... And maybe watch Lucy play with Erza," she crooned, sliding herself right into his lap, and kissed him. He placed a hand on the back of her head, and deepened the kiss.

"...so, what do you want to do, Ma'am?" Erza asked Lucy, who had pulled up her top to expose her boobs, Lisanna and Natsu watching out of the corner of their eyes.

"Hmm... What indeed?" Lucy asked, cupping Erza's breasts as she considered the question.