Causative Form
Add -saseru, -sasemasu to the stem of v-stem verbs (-sasenai, -sasemasen for the negative), and add -aseru, -asemasu to the stem of c-stem verbs (-asenai, -asemasen for the negative).
トラコを台所のテーブルから下りさせました。
Torako o daidokoro no teeberu kara orisasemashita.
I made Torako get off the kitchen table.
This page is a part of "Some Notes on
Japanese Grammar" published for your personal use, with the kind
permission of Keith Smillie (http://www.cs.ualberta.ca/~smillie/)
iku -> ika + saseru = ikasaseru
au -> awa + saseru = awasaseru
Note that when the last syllable of a dictionary form is "u", it changes to "wa"-- alien-san's inflection was incorrect.
taberu -> tabe + saseru = tabesaseru (ichidan verb)
suru and kuru are irregular, but again the stems used are the same ones used with -nai:
suru -> shinai, shisaseru
kuru -> konai, kosaseru
This information is explained on the main page on Verbs, http://www.studyjapanese.org/language-reference/verbs .
The -saseru and -aseru endings inflect the same way ichidan (ru-dropping) verbs inflect, so the polite inflections are -sasemasu, -sasemasen (negative), -sasemashita (past), -sasemasendeshita (negative past), and similarly for -aseru.
@alynne-san: So -sasemasen and -asemasen are the endings for causative negatives in the present/future tense, not past negatives.