To allocate a block of memory you can use the allocate
You may optionally pass the --read, --write and --execute options to set the access permissions of the memory block. If none of these options are used, the block gets full access.
Here's how you would allocate 8 bytes in the program whose PID is 12345:
$ proctal allocate --pid=12345 8
It will print the starting address of the block of memory.
When you're done, you have to deallocate the block by passing the same address to the deallocate command. If the address were 7FFE79DEA90C, the command would look like this:
$ proctal deallocate --pid=12345 7FFE79DEA90C