Similar to a danger
wank in that the process involves masterbating while fully aware of the very real danger of being caught out, either by a parent, family member, work colleague, etc. The difference is that with a Meerkat Wank you are standing up whilst having a danger
wank, and so are straining your head and
neck whilst listening and looking out for anyone who might catch you in the
act. Looking like a meerkat standing sentry on it's rear legs as you do so.