How to store "infixes"

I need to store all possible infixes of words (and their location) to be able to quickly make queries.

(eg. anus -> a, n, u, s, an, nu, us, anu, nus, anus)

Problem is, even with small files, if you store "infix->list of positions", the index gets really really really large (obviously).

I have been trying to think of a data structure to reduce storage needed, but... I failed. Any ideas?

We all realize this is set-up, so please just gtfo. You ask a question you've answered a priori. Even the answer post might be written a priori; but not necessarily. What you gain from this, is that you're able to associate your stupid junk with programming posts, thus giving the illusion that programmers here actually talk about this bullshit (your stupid shit).