A skullclamp is a fiercely painful erotic act in which one partner inserts his head into the urethra of the second parter (obviously male) and then has the second partner attempt to squeeze the first partner's temples with his penis while fingering the anus of the said first partner.
Dude, me and Zack tried the Skullclamp last night." "yeah, how'd it go?" "well, he'll be out of the hospital by noon tomorrow......
A hardo is a person who tries extremely hard at everything. Most times a hardo will try very hard at things that do not require excessive effort. For example, sports practices, gym class, etc.
Wow did you see Jack at practice today? What a hardo!