3rd person:

Sans and Papyrus was snuggling on the couch until Sans sat up and looked at Papyrus "So...Bro, you need to go to Grillbys , I haven't been there for a few days and I don't want him to worry."
"UUUUUUUGGGGGGGHHHHHHHHH Sans... PLEASE!"
"Well ... I could just go like this and let everyone think we've swapped personalities" Papyrus was looking at Sans with pure shock he was blackmailing him! "Ugh! Fine!" "Great! Just ask for the usual and and you'll be fine, and if anyone tells you anything tell me when you get back ok?" "Sure Sans..."

Papyrus' POV (at grillbys)

"Hey Sans" "Hi Sans" "Hiya Sansy~"
Everybody loved him, just got to sound like him... hmm "Heya everybody" I went to Sans' favourite bar stool "Hi Sans" "Sup Grillby" This was going to be a looooooong night... "The usual yes?"
"Yeah thanks Grillby" he gave me some sort of red drink, it looked like ketchup, yet smelled like alcohol, I took a huge mouthful of it, to be honest it didn't taste so bad... But I'll never drink it again when I get back into my body.

After 9 shots of alcoholic ketchup

Sans' POV:

*ring ring*

"Hello? This is the great Papyrus speaking" "Hey Papyrus... I need you to come pick up Sans" What? Papyrus has gone and gotten himself drunk? Maybe it's all an act to be more like me? "Ok Grillby, I'll be there shortly" "Thank you, Papyrus"

*At grillbys*

"Ok, I'm here Grillby, where is he?"
Papyus was sitting at the bar, my hoodie hanging off him, oh god he is actually drunk... "Oh h-*hic*-hi Ssanss"
NO! He's going to bring suspicion "Um Sans? You mean Pap right? Nyeh heh..." I quickly pick up pap and thank Grillby, then start to walk home, slowly I start to pick up the pace and run.

"Pap! You almost gave us away!" "Oh... Sorry Sans, I *hic* just forgot" Suddenly without warning I feel Pap's scarf get ripped off me, "Pap? What are you doing?" Papyrus just looked at me and grinned in a blink of an eye my hands were tied up by his scarf...