How do you deal with guests who can't take a hint?

Stop beating around the G*DD**N bush and tell them straight-up.

Talk about cramps and tampons.... try that. 

Ask them if they would like to have a farting contest.

~

call the pigs

Exactly the same way as those that take my Mints...:) 

Say it directly.
Be polite and assertive.
E.g., "I'm tired and I need you to leave now so that I can get some sleep."
Use the broken record technique ( exact repetition) until they start to leave.
Don't respond if they try to engage you in further conversation.
Escort them to your door, gate or their car.
Say a polite and (not overly) friendly good-bye.

If they query it sometime later, stand your ground.

Stop hinting. Speak plainly.