back-to-back vs consecutive

back-to-back and consecutive both are adjectives.

Word	Noun	Adjective	Verb	Adverb
back-to-back	No	Yes	No	No
consecutive	No	Yes	No	Yes

As adjectives, back-to-back and consecutive are synonyms defined as:

back-to-back (adjective)	consecutive (adjective)
one after the other	successive (without a break)
	in regular succession without gaps
	one after the other

back-to-back (adverb)	consecutive (adverb)
	in a sequential manner