Want to do a cream or custard pie, but want to use an alternative for "squirty" cream as it often goes runny too quickly. What could you guys suggest?

Are you in Britain or the USA? My advice will apply to the UK only.

There is no ready made solution. As the previous poster suggests: dairy double cream, whipped by manual or electric whisk OR double cream alternative (Tesco) prepared in the same way. They behave slightly differently but basically, real dairy cream will whip and clot until it is very formed and firm (but becomes less sticky); the alternative (based on veg oil) takes longer to whip but stays sloppy and sticky when formed. Take a look at the pies in my trailers and GIFs. Quantity increases visual effectiveness.