Foutre is a defective verb. It can not be conjugated in all possible forms.
Here are several examples of defectives verbs:
paître.
Foutre verb is conjugated in female form and in reflexive form. Be careful, the past participle of compound tenses must agree with the subject.
Foutre verb is conjugated in interrogative form. For sound reasons, an euphonious
« t » is added to the pronoun of the third person:
« il »,
« elle »,
« on »,
« ils »,
« elles » except when the verb ends with
« t » or
« d »:
« foutra-t-elle ">« aura-t-elle foutu ? ».
Finally, the interrogative form does not exist in subjunctive and imperative.