How to insert <TAB> after word?

Our coding standard require to insert <TAB> after type name on variable/field declaration:
```c
struct A {
  size_t/*TAB here*/fsize;
  size_t/*and I try to type it here*/
};
```
When I type `size_t` autocompletion window pops up, and <TAB> starts choose of variants, and I don't get how to insert just <TAB> itself.

Can you help me?