"Gnu, a hint: unlocker, English, R2 times this gives you something round."

No MM, not Key Lime Pie... "R squared times" obviously refers to the olden times of the infamous "English" knight of the "round" table, Sir Ralph of Rotten (Rotten Ralphy) who was ruthless on the battlefields during the crusades. When he got back, he would "unlocker". It's clearly a chastity belt.

Gee, I wouldn't think much of a present like that myself. Must be some kinda English humour eh?