Whenever the ablative form of this pronoun is the object of the preposition cum, the word cum is attached to the end of it. So,

• quocum --> with whom or with which
• quacum --> with whom or with which
• quibuscum --> with whom or with which (pl.) 

Singular

​	Masculine ♂	Feminine ♀	Neuter ⚲
Nominative	qui ​​​who; which/that	quae who; which/that	quod which/that
Genitive	cuius whose/of whom; of which	cuius whose/of whom; of which	cuius of which
Dative	​cui to/for whom / which	cui to/for whom / which	cui to/for which
Accusative	quem ​whom; which/that	quam whom; which/that	quod which/that
Ablative	quo by, with, from etc. whom/which	qua by, with, from, etc. whom/which	quo by, with, from, etc. which

Plural

​	Masculine ♂	Feminine ♀	Neuter ⚲
Nominative	qui ​​​who; which/that	quae who; which/that	quae which/that
Genitive	quorum whose/of whom; of which	quarum whose/of whom; of which	quorum of which
Dative	​quibus to/for whom / which	quibus to/for whom / which	quibus to/for which
Accusative	quos ​whom; which/that	quas whom; which/that	quos which/that
Ablative	quibus by, with, from etc. whom/which	quibus by, with, from, etc. whom/which	quibus by, with, from, etc. which