Breakdown of Luego, quiero secarlo con la toalla.
con
with
luego
later
querer
to want
lo
it / him (direct object)
Questions & Answers about Luego, quiero secarlo con la toalla.
Why is lo attached to the end of secar? Can I put it somewhere else?
Because secar (to dry) is in its infinitive (unconjugated) form, you can attach the direct object pronoun lo (it) directly to the end to make secarlo. But because it follows the conjugated verb quiero, you can also move the pronoun to the very front of the verb phrase: Luego, lo quiero secar con la toalla. Both are perfectly correct and mean the exact same thing!
Why does this sentence use lo for "it"? Could it be la?
In Spanish, "it" must match the gender of the noun you are talking about. lo is used here because the speaker is drying a masculine noun (like el pelo, the hair, or el perro, the dog). If they were drying a feminine noun like la ropa (the clothes), they would use la and say quiero secarla.
How would I change this if I wanted to say "I want to dry myself"?
To say you are performing the action on yourself, you need the reflexive pronoun me. You would say quiero secarme or me quiero secar. Because this sentence uses lo, we know the speaker is drying a separate object, not themselves.