How do i lazy load entities inside aggregate if repositories are not allowed inside it

I was recently reading DDD and came across the guideline that repositories are not allowed inside our aggregates. Now, If we follow this guideline then it would mean that we have to load all the entities and value objects inside aggregates when we create/restore the root from database, but what if the number of entities/value objects are huge and i want to lazy load them, how do i achive that without access to repository, what is the standard way of achiving this.