diff --git a/README.md b/README.md
index 02638474..f82e45f8 100644
--- a/README.md
+++ b/README.md
@@ -457,6 +457,10 @@ using a combination of `bwa` and `samtools` to output a BAM file instead of a SA
 
 - If the tool supports multi-threading then you MUST provide the appropriate parameter using the Nextflow `task` variable e.g. `--threads $task.cpus`.
 
+- If a module contains _multiple_ tools that supports multi-threading (e.g. [piping output into a samtools command](https://github.com/nf-core/modules/blob/28b023e6f4d0d2745406d9dc6e38006882804e67/modules/bowtie2/align/main.nf#L32-L46)), you MUST assign cpus per tool such that the total number of used CPUs does not exceed `task.cpus`.
+    - For example, combining two (or more) tools that both (all) have multi-threading, this can be assigned to the variable [`split_cpus`](https://github.com/nf-core/modules/blob/28b023e6f4d0d2745406d9dc6e38006882804e67/modules/bowtie2/align/main.nf#L32)
+    - If one tool is multi-threaded and another uses a single thread, you can specify directly in the command itself e.g. with [`${task.cpus - 1}`](https://github.com/nf-core/modules/blob/6e68c1af9a514bb056c0513ebba6764efd6750fc/modules/bwa/sampe/main.nf#L42-L43)
+
 #### Software requirements
 
 [BioContainers](https://biocontainers.pro/#/) is a registry of Docker and Singularity containers automatically created from all of the software packages on [Bioconda](https://bioconda.github.io/). Where possible we will use BioContainers to fetch pre-built software containers and Bioconda to install software using Conda.