Eager sex at church ending in ignominy (5)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

IT (slang for sexual activity) + CH (abbreviation for church) + end letter of [ignomin] Y . I think I’d use “itching” rather than “itchy” to mean eager (as in “itching to get started”), but Collins recognises this usage.