I was really disappointed that there is teapot in my daughter's Duplo house but no mugs to actually drink tea from. 

So I designed this mug and it came out pretty nice, fit into characters' hand perfectly, size is not too large to look ugly and not too small for child to play with. 

Printing:

Layer area is quite small so you may encounter ugly warping on handles as printer can't properly cool it down in time. This can be avoided if you print multiple mugs at the same time. 

I used 0.6mm nozzle, 0.15mm layer height, printed 4 mugs and it came out perfect. 

Designed in OnShape:

https://cad.onshape.com/documents/5abd9ab23c660d3fdfa1d1a3/w/78260171d2958e16db274475/e/e08540ab0564342b10920254