The humor and irony in the statement "got blow" relies heavily on its context and interpretation. As an initial matter, one must understand that "blow" holds a number of connotations. Therefore, its inherent ambiguity can give rise to a myriad of interpretations. In some informal contexts, 'blow' term might refer to cocaine, but it could also mean a physical strike or to expend effort (as in 'blowing' on a hot beverage to cool it). The statement might be quoted in a context that hilariously undermines or twists projection, producing an unexpected outcome, which can tickle the funny bones of some.
As an example, if "got blow" is used amongst a group of friends who are enthusiastic brass instrument musicians, the word 'blow' could be construed in a musical sense, denoting blowing into their musical instruments. Here, any irony or wit would derive mostly from the contrast between this rather innocent interpretation versus the more risqué possibilities that "got blow" might suggest in different context, which refers to illicit substance use.
The humorous interpretation is contingent on the speaker, listener, and their shared context. One might be caught in a turbulent wind, receiving a 'blow' from the gust, and jokingly declare "got blow". It's ironic because the person isn't really benefiting like one who got something convenient but instead psyched by the unexpected gust. Furthermore, if the listener was expecting a serious response, this would present as even more humorous.
A situation could be considered ironic if the person who says "got blow" is assumed to imply the use of drugs but indeed refers to a physical blow. For instance, if the statement was said in a party scene where drug use is rampant, but the speaker got hit by an accidentally tossed bottle, the ambiguity combined with the environment makes it seem like "got blow" might refer to the acquiring of a substance. That's why when the truth is exposed, it's found ironically humorous by the listeners due to the shift of the context.
The humor can also stem from the usages of "got" that connotes possession. In a more mundane example, if it is said directly after trying to cool a coffee by blowing on it and then sipping only to find it's still hot, it suggests the person has been 'blown' by the steam of the hot cup, indicating a certain defeat. They expected relief, but instead 'got blow'. Hence, the phrase is humorously ironic because it uses colloquial language to express a fairly common and mundane experience.
Lastly, the statement’s succinctness adds to its overall humor. "Got blow" lacks grammatical sophistication; it is direct and does not elaborate on the situation's details, resulting in deadpan humor or a humorous matter-of-fact statement. The humor arises from the unexpectedness of the phrase's brevity, leaving much to the listener's imagination. Therefore, the phrase can be both funny and ironic, depending on the context and the receiver's interpretation. got blow