That's kind of a tricky one. If I was you, I'd start by asking him "how would you like to have a threesome with me and...?"
It's pretty simple. I've known one guy my entire life who was not up for a threesome with two women.
She slyly passed the secret note to her friend during class without the teacher noticing.
The stem word for slyly is sly.
The adverb of "sly" is "slyly."
Slyly
Yes, "slyly" is an adverb. It is used to modify a verb, usually indicating that something is done in a cunning or stealthy manner.
Cheekily and slyly ;)
peep
slyly
Secretly Slyly & With A Lot Of Time On Your Hands
Slyly hint to him that your mother still has feelings for your father.
artfully; craftily; foxily; slyly; knavishly; trickily;
slyly