After writing two different replies I noticed that perhaps I have more thoughts and feels about this question than can be contained in 140 or even 280 characters.
First off the answer is simple. No. Consent isn't sexy.
There is a huge campaign surrounding the notion that it is and I think it is bull. Or at least too narrowly framed.
There are many non-sexy contexts in which we use the tool of consent.
Consent can be decidedly unsexy when in order to travel by plane we must consent to have our bodies and out belongings searched.
But consent outside sexy contexts doesn't have to be unsavory. On the adorable but certainly non sexy end we have a parent saying yes and allowing their 7 year old son to crawl onto their back for the piggy back ride he's been begging for.
In the questionable middle ground there're many kinds of legal and medical consent that have absolutely nothing to do with sex at all and are unlikely to inspire the arousal of most.
Don't get me wrong consent is extremely useful in sexy contexts. It helps prevent harm. It helps us get clear on our sexual wants and boundaries.
It helps make sex (and other interactions) easier and more doable for those who are interested in doing it with others regularly. On a societal level consent makes sex a more sustainable way of interacting and reduces the physical, mental, and emotional harm we do to each other.
But the consent itself is not sexy in and of itself. In the same way that our bodies and body parts aren't always sexy because we don't always consider them to be. When I'm not aroused or thinking about things/people in a sexy context having my body or parts of it objectified or identified as others as "sexy" can leave me feeling violated/dehumanized.
The claim that "consent is sexy" falls apart especially in the case of asexual folks. Consent, and even consent surrounding intimacy totally exists for asexual people. It's just not sexy. Which is TOTALLY FINE. In the same way that not all sex attracts all people, not all communications of consent are universally sexy.
Consent itself is not what we find sexy. The unique ways that individual people give consent can be vey sexy but that's the delivery not message not consent itself. What we find sexy is their words/behavior. In this sense the delivery of consent can be extremely sexy, however this sexiness is completely subjective.
For instance I once asked a woman I didn't know very well but was attracted to (we'd both been drinking at a party) if I could top her sometime. She smiled, turned around and bent over to signal her consent. Had we been in another context I would've probably found this very sexy, but because I didn't know her very well and we were in a room with other partygoers, I felt a little intimidated, anxious, and even felt pressure to "act more toppy" in that moment. Any "sexy" I'd been feeling in that moment was swallowed up by my social anxiety. This person was consenting to something I asked for (and we did get to play later) but the way she communicated her consent intimidated me and was not sexy to me in that moment.
Fortunately, more often than not, we're going to find the ways that people we're attracted to communicate their consent to sexual activity with us to be sexy. This doesn't mean that the consent is sexy. It means that you find the way that person communicates sexy. Which is actually much more intimate than seeing consent as the sexy stuff. This way of thinking gives me the freedom to give compliments like “I love the way you do consent.” and “The way you say yes is really fucking sexy.”
Now I'm not going to yell at or angrily correct someone saying "consent is sexy". In fact when I hear people using this phrase I'm able to identify them as potential allies in my community. People who say this care about consent and building less harmful and more sustainable sexual practices. And these are people I want to connect and collaborate with.
That said my politics place focus more on consent more than they do on sex. As a consent-positive advocate for less harmful human interactions I'm annoyed when the tools of consent are limited to the context of sexuality. The phrase "consent is sexy" at worst enforces this limitation. At best it does not do what the necessary work of broadening awareness about and use of consent in all human interactions (not just the sexy ones).