Present participle; Past participle - thwacking - thwacked Present - thwack - thwack - thwacks - thwack - thwack - thwack Past - thwacked - thwacked - thwacked - thwacked - thwacked - thwacked Future - will thwack - will thwack - will thwack - will thwack - will thwack - will thwack Present conditional - would thwack - would thwack - would thwack - would thwack - would thwack - would thwack Present Perfect - have thwacked - have thwacked - has thwacked - have thwacked - have thwacked - have thwacked Past Perfect - had thwacked - had thwacked - had thwacked - had thwacked - had thwacked - had thwacked Future Perfect - will have thwacked - will have thwacked - will have thwacked - will have thwacked - will have thwacked - will have thwacked Past conditional - would have thwacked - would have thwacked - would have thwacked - would have thwacked - would have thwacked - would have thwacked Imperative - - - thwack - - - - - - - -