must headbutt
Regular verb: headbutt - headbutted- headbutted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must headbutt
you must headbutt
she must headbutt
we must headbutt
you must headbutt
they must headbutt 	I must be headbutting
you must be headbutting
she must be headbutting
we must be headbutting
you must be headbutting
they must be headbutting	I must have headbutted
you must have headbutted
she must have headbutted
we must have headbutted
you must have headbutted
they must have headbutted	I must have been headbutting
you must have been headbutting
she must have been headbutting
we must have been headbutting
you must have been headbutting
they must have been headbutting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't headbutt
you mustn't headbutt
she mustn't headbutt
we mustn't headbutt
you mustn't headbutt
they mustn't headbutt 	I mustn't be headbutting
you mustn't be headbutting
she mustn't be headbutting
we mustn't be headbutting
you mustn't be headbutting
they mustn't be headbutting	I mustn't have headbutted
you mustn't have headbutted
she mustn't have headbutted
we mustn't have headbutted
you mustn't have headbutted
they mustn't have headbutted	I mustn't have been headbutting
you mustn't have been headbutting
she mustn't have been headbutting
we mustn't have been headbutting
you mustn't have been headbutting
they mustn't have been headbutting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I headbutt?
must you headbutt?
must she headbutt?
must we headbutt?
must you headbutt?
must they headbutt? 	must I be headbutting?
must you be headbutting?
must she be headbutting?
must we be headbutting?
must you be headbutting?
must they be headbutting? 	must I have headbutted?
must you have headbutted?
must she have headbutted?
must we have headbutted?
must you have headbutted?
must they have headbutted? 	must I have been headbutting?
must you have been headbutting?
must she have been headbutting?
must we have been headbutting?
must you have been headbutting?
must they have been headbutting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I headbutt?
mustn't you headbutt?
mustn't she headbutt?
mustn't we headbutt?
mustn't you headbutt?
mustn't they headbutt? 	mustn't I be headbutting?
mustn't you be headbutting?
mustn't she be headbutting?
mustn't we be headbutting?
mustn't you be headbutting?
mustn't they be headbutting? 	mustn't I have headbutted?
mustn't you have headbutted?
mustn't she have headbutted?
mustn't we have headbutted?
mustn't you have headbutted?
mustn't they have headbutted? 	mustn't I have been headbutting?
mustn't you have been headbutting?
mustn't she have been headbutting?
mustn't we have been headbutting?
mustn't you have been headbutting?
mustn't they have been headbutting?