Being slow in everything you do, almost slug-like; hence the refernce to the alien slug from Star Wars.
And refer to movement speed or general sloth like behaviour.
Impressions of Jabba can be done whilst in their presence to keep the joke on the low.
A- Where's James gone?
B- He'll be a while, he's Jabba the Hutt.
...5 minutes later...
A- Here he comes
B- Ha Jo Delo Hum Ti Hada Jedi Scum.