Originally Posted by Vendot

That's a tough call.

So it really depends on what the two options actually are. Google has reduced the importance of a keyword in the domain name long ago but it will still help users to find you. Assuming dot com in both cases below:

If its between KinkyTube and KTube, I choose KinkyTube because its not that long or remember.

If its between KinkyBDSMsexTube and KTube, I choose KTube because:

(a) Much easier to remember.

(b) Much easier to type.

(c) Short and better for branding.

(d) The longer option will loose you a lot of traffic through typos.

(e) There are not that many popularly used words starting with K other than Kinky and people would probably first think of K as relating to Kinky. So the association with letter K will probably work well once the users understand your product.