What is the ruling on putting money with drawings of mosques, bearing the names of those mosques, in the back pocket and sitting on it? What is the desecration that amounts to disbelief? And what is the ruling on laughing at disbelief without supporting it?

Placing money with a picture of a mosque in the back pocket and sitting on it incurs no blame due to widespread prevalence (umūm al-balwā) and because generally there is no intention of disrespect. However, it is preferable to avoid sitting on it. Disrespect becomes disbelief (kufr) if it indicates mockery of the religion and its symbols. A listener's laughter at one who mocks the religion, if it occurs due to being overwhelmed or for a purpose other than consenting to disbelief, is not considered disbelief. The question seems to indicate the presence of intrusive thoughts (waswasah), and it is advised to supplicate, disregard them, and consult a psychiatrist.