I really like that first R. Especially if you can roll it just a bit. Then the flow stops abruptly at that P. It's like they had two words and just slammed them together hoping no one would notice. But the sexy S makes up for and the double L and yuhn to wrap it up. Wonderful.
Also, I think what helps make this word sexy is that the people who say it inevitably have British accents. Or maybe Irish. Either way, that's sexy.
So what is a rapscallion?
It's like you all said "You!" at exactly the same time. Thanks. Well, maybe, but I'll never admit to it. To being--
a rascal; rogue; scamp.