What is the meaning of: "Even if he were to ask her for herself while she is on a saddle, she would not withhold herself"?

It is mentioned in the Hadith (definition) that a woman does not fulfill the right of her Lord until she fully fulfills the right of her husband, even if he requests her for intercourse while she is on a "qatab" (a small saddle on the hump of a camel), she should not refuse him. The "qatab" here signifies that she is in a state of postnatal bleeding and childbirth. This indicates an exaggeration in urging the woman to enable her husband to have access to her and not to refuse him, even under the most difficult circumstances. Abu Ubayd al-Qasim ibn Sallam explained this meaning by saying that the woman used to be seated on the qatab to facilitate her childbirth.