help for the sentence meaning

[lorenya]

Hi. I need your help once again to understand the meanings of the following sentences in the novel I'm trying to translate:

In the next few weeks he had his eyes so zeroed in on old u.t. he couldn't see elephant poo in front of him if it were dump-truck high. Ain't no wonder then that during this time he got a lot of you-know-what on his shoes. (I couldn't figure out what this second sentence means)

Billy jogged down the filed to clap him on the back (and cause the first of his many fumbles). (American football is not known well here. Could you please simply explain what is going on here?)

Which side of you do you want me to pretend is the laces? (What does he mean by laces while this bully threatens a small boy?)

Thanks in advance.

[Soup]

Hello lorenya

... he couldn't see elephant poo in front of him if it were dump-truck high. Ain't no wonder then that during this time he got a lot of you-know-what on his shoes;

that is, he stepped in a lot of "poo" while at the zoo.

Billy jogged down the field to clap him on the back (and cause the first of his many fumbles).

To clap someone on the back is to congratulate that person.

Which side of you do you want me to pretend is the laces?

A football has laces. Could the boy be threatening to throw the other boy as one does a football? More context would help.