Tess = singular

Tess's = singular possessive

Tesses = plural

Tesses's plural possessive

To spell the plural of most names that end in S, you would add -es.

Example: Jones-Joneses, Tess-Tesses

you get the toy truck but first you need to go to the top of the book case and push Tesses Tree off. Then you get the toy truck, you ride it up the ramp of books and if that dosent work that SOL (so outta luck) But its ok because that happened to me =( sorry!

Whilst it is more common to see it just with an apostrophe on the end, e.g. Lucas', it is actually more correct to write it with an extra s, e.g. Lucas's.